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Connecticut, USAi
Regional Level Types
ConnecticutState
USACountry

This page kindly sponsored by Harold Moritz
Key
00539120014946283395580.jpg
Mine Exploration

Connecticut, USA
04683050014946313161369.jpg
Winze Or Sump?

Connecticut, USA
07209270014946313135885.jpg
Mine Exploration

Connecticut, USA
00539120014946283395580.jpg
Mine Exploration

Connecticut, USA
04683050014946313161369.jpg
Winze Or Sump?

Connecticut, USA
07209270014946313135885.jpg
Mine Exploration

Connecticut, USA
00539120014946283395580.jpg
Mine Exploration

Connecticut, USA
05915700014946313161796.jpg
Winze Or Sump?

Connecticut, USA
Area:
14,357 km2
Locality type:
Largest Settlements:
PlacePopulation
Bridgeport147,629 (2017)
New Haven130,322 (2017)
Stamford128,874 (2017)
Hartford124,006 (2017)
North Stamford121,230 (2017)
Waterbury108,802 (2017)
Other Languages:
French:
Connecticut, États-Unis
German:
Connecticut, Vereinigte Staaten
Italian:
Connecticut, Stati Uniti d'America
Russian:
Коннектикут, Соединённые Штаты Америки
Simplified Chinese:
康乃狄克州, 美国
Spanish:
Connecticut, Estados Unidos
Afrikaans:
Connecticut, Verenigde State van Amerika
Albanian:
Connecticut, Shtetet e Bashkuara të Amerikës
Amharic:
ኮነቲከት, አሜሪካ
Anglo-Saxon:
Connecticut, Geānedu Rīcu American
Arabic:
كونيتيكت, الولايات المتحدة
Aragonese:
Connecticut
Armenian:
Կոնեկտիկուտ, Ամերիկայի Միացյալ Նահանգներ
Asturian:
Connecticut, Estaos Xuníos d'América
Aymara:
Connecticut suyu, Istadus Unidus
Azeri:
Konnektikut, Amerika Birləşmiş Ştatları
Basque:
Connecticut
Bavarian:
Connecticut, Vaoanigte Stootn
Belarusian:
Канектыкут, Злучаныя Штаты Амерыкі
Belarusian (Tarashkevitsa):
Канэктыкут, Злучаныя Штаты Амэрыкі
Bengali:
কানেটিকাট, মার্কিন যুক্তরাষ্ট্র
Bishnupriya Manipuri:
কানেকটিকাট, তিলপারাষ্ট্র
Bislama:
Connecticut, Yunaeted Stet blong Amerika
Bosnian:
Connecticut, Sjedinjene Američke Države
Breton:
Connecticut, Stadoù-Unanet Amerika
Bulgarian:
Кънектикът, Съединени американски щати
Burmese:
ကွန်နက်တီကတ်ပြည်နယ်, အမေရိကန်ပြည်ထောင်စု
Catalan:
Connecticut, Estats Units d’Amèrica
Cebuano:
Connecticut
Central Bikol:
Connecticut, Estados Unidos
Chechen:
Коннектикут, Америкин Цхьаьнатоьхна Штаташ
Chuvash:
Коннектикут, Пĕрлешнĕ Штатсем
Cornish:
Connecticut, Statys Unys
Corsican:
Connecticut, Stati Uniti d'America
Croatian:
Connecticut, Sjedinjene Američke Države
Czech:
Connecticut, Spojené státy americké
Danish:
Connecticut, USA
Dutch:
Connecticut, Verenigde Staten
Dutch Low Saxon:
Connecticut, Verienigde Staoten van Amerika
Egyptian Arabic:
كونيتيكت, امريكا
Emilian-Romagnol:
Connecticut, Stat Unî
Esperanto:
Konektikuto
Estonian:
Connecticut, Ameerika Ühendriigid
Faroese:
Connecticut
Farsi/Persian:
کنتیکت, ایالات متحده آمریکا
Fiji Hindi:
Connecticut, United States
Finnish:
Connecticut, Yhdysvallat
Franco-Provençal:
Connecticut, Ètats-Unis
Gagauz:
Connecticut, Amerika Birleşik Devletläri
Galician:
Connecticut, Estados Unidos de América
Georgian:
კონექტიკუტი, ამერიკის შეერთებული შტატები
Greek:
Κονέκτικατ, Ηνωμένες Πολιτείες Αμερικής
Guarani:
Connecticut, Tetãvore Joapykuéra
Haitian:
Konèktikòt, Etazini
Hakka:
Connecticut
Hausa:
Connecticut, Tarayyar Amurka
Hawaiian:
Konekikuka, ‘Amelika Hui Pū ‘ia
Hebrew:
קונטיקט, ארצות הברית
Hill Mari:
Коннектикут, Америкын Ушымы Штатвлӓжӹ
Hindi:
कनेक्टिकट, संयुक्त राज्य
Hungarian:
Connecticut, Amerikai Egyesült Államok
Icelandic:
Connecticut, Bandaríkin
Ido:
Connecticut, Usa
Igbo:
Kónétíkùt, Njikọ̀taọ̀hà
Iloko:
Connecticut, Estados Unidos iti Amerika
Indonesian:
Connecticut, Amerika Serikat
Interlingua:
Connecticut, Statos Unite de America
Irish Gaelic:
Connecticut, Stáit Aontaithe Mheiriceá
Japanese:
コネチカット州, アメリカ合衆国
Javanese:
Connecticut, Amérika Sarékat
Judaeo-Spanish:
Connecticut, Estados Unidos de Amerika
Kabiye:
Kɔnɛtɩkuti, Etaazuunii
Kabyle:
Connecticut, Iwunak Yeddukklen n Temrikt
Kalmyk:
Коннектикут, Америкин Ниицәтә Орн Нутугуд
Kannada:
ಕನೆಕ್ಟಿಕಟ್, ಅಮೇರಿಕ ಸಂಯುಕ್ತ ಸಂಸ್ಥಾನ
Kapampangan:
Connecticut, Estados Unidos
Kazakh (Cyrillic Script):
Коннектикут, Америка Құрама Штаттары
Khmer:
ខុនណេកទីខាត់, សហរដ្ឋអាមេរិក
Korean:
코네티컷주, 미국
Kurdish (Latin Script):
Connecticut, Dewletên Yekbûyî yên Amerîkayê
Latin:
Connecticuta, Civitates Foederatae Americae
Latvian:
Konektikuta, Amerikas Savienotās Valstis
Ligurian:
Connecticut, Stati Unïi d'America
Limburgian:
Connecticut, Vereinegde Staote vaan Amerika
Lithuanian:
Konektikutas, Jungtinės Amerikos Valstijos
Lombard:
Connecticut, Stat Ünì d'America
Low Saxon/Low German:
Connecticut, USA
Luri:
کانتیکئت, ڤولاتچٱیا یٱکاگرتٱ آمریکا
Luxembourgish:
Connecticut, Vereenegt Staate vun Amerika
Macedonian:
Конектикат, Соединети Американски Држави
Maithili:
कनेक्टिकट, संयुक्त राज्य अमेरिका
Malagasy:
Connecticut, Etazonia
Malay:
Connecticut, Amerika Syarikat
Malayalam:
കണെക്റ്റിക്കട്ട്
Manx:
Connecticut, Steatyn Unnaneysit America
Maori:
Connecticut, Hononga-o-Amerika
Marathi:
कनेक्टिकट, अमेरिकेची संयुक्त संस्थाने
Mazanderani:
کنتیکت
Meadow Mari:
Коннектикут, Ушымо Американ Штат-влак
Min Dong Chinese:
Connecticut
Mingrelian:
კონექტიკუტი, ამერიკაშ აკოართაფილი შტატეფი
Mongolian:
Коннектикут, Америкийн Нэгдсэн Улс
Nauruan:
Connecticut, Eben Merika
Nepali:
कनेक्टिकट, संयुक्त राज्य अमेरिका
Newar / Nepal Bhasa:
कनेक्तिकत, संयुक्त राज्य अमेरिका
Northern Frisian:
Connecticut, Feriind Stoote foon Ameerika
Northern Sami:
Connecticut, Amerihká ovttastuvvan stáhtat
Norwegian:
Connecticut, USA
Norwegian (Nynorsk):
Connecticut, USA
Occitan:
Connecticut, Estats Units d'America
Ossetian:
Коннектикут, Америкæйы Иугонд Штаттæ
Pali:
कनेक्टिकट, संयुक्त राज्य अमेरिका
Pennsylvania German:
Connecticut, Amerikaa
Piedmontese:
Connecticut, Stat Unì d'América
Polish:
Connecticut, Stany Zjednoczone
Portuguese:
Connecticut, Estados Unidos
Punjabi:
ਕਨੈਟੀਕਟ, ਸੰਯੁਕਤ ਰਾਜ ਅਮਰੀਕਾ
Quechua:
Connecticut suyu, Hukllachasqa Amirika Suyukuna
Romanian:
Connecticut, Statele Unite ale Americii
Romansh:
Connecticut, Stadis Unids
Russia Buriat:
Коннектикут
Samogitian:
Konektėkots, JAV
Sanskrit:
कनेक्टिकट्, अमेरिकासंयुक्तराज्यम्
Sardinian:
Connecticut, Istados Unidos de Amèrica
Saterland Frisian:
Connecticut, Fereende Stoaten fon Amerikoa
Scots:
Connecticut
Scottish Gaelic:
Connecticut, Na Stàitean Aonaichte
Serbian:
Конектикат, Сједињене Америчке Државе
Serbo-Croatian:
Connecticut, Sjedinjene Američke Države
Sicilian:
Connecticut, Stati Uniti
Silesian:
Connecticut, Zjednoczůne Sztaty
Slovak:
Connecticut, Spojené štáty
Slovenian:
Connecticut, Združene države Amerike
South Azerbaijani:
کانتیکت ایالتی, آمریکا بیرلشمیش ایالتلری
Swahili:
Connecticut, Marekani
Swedish:
Connecticut, USA
Tagalog:
Connecticut, Estados Unidos
Tamil:
கனெடிகட், அமெரிக்க ஐக்கிய நாடு
Tatar:
Коннектикут, Америка Кушма Штатлары
Telugu:
కనెక్టికట్, అమెరికా సంయుక్త రాష్ట్రాలు
Thai:
รัฐคอนเนตทิคัต, ประเทศสหรัฐอเมริกา
Traditional Chinese:
康湼狄格州, 美國
Turkish:
Connecticut, Amerika Birleşik Devletleri
Ukrainian:
Коннектикут, Сполучені Штати Америки
Upper Sorbian:
Connecticut, Zjednoćene staty Ameriki
Urdu:
کنیکٹیکٹ, ریاستہائے متحدہ امریکا
Uyghur:
Konnéktikat Shitati, ئامېرىكا قوشما شىتاتلىرى
Uzbek (Latin Script):
Konnektikut, Amerika Qoʻshma Shtatlari
Vietnamese:
Connecticut, Chủng Quốc Hoa Kỳ
Volapük:
Connecticut, Lamerikän
Waray:
Connecticut, Estados Unidos
Welsh:
Connecticut, Unol Daleithiau America
West Frisian:
Konettikut, Feriene Steaten
Western Punjabi:
کنکٹیکٹ, امریکہ
Wu Chinese:
康涅狄格, 美国
Xhosa:
IKhonethikhati, IYunayithedi Steyitsi
Yakut:
Коннектикут, Америка Холбоһуктаах Штааттара
Yiddish:
קאנעטיקעט, פאראייניקטע שטאטן פון אמעריקע
Yoruba:
Connecticut
Zazaki:
Connecticut, Dewletê Amerikayê Yewbiyayey
Zeelandic:
Connecticut, Vereênigde Staeten
Zulu:
Connecticut, IMelika


Hierarchy:
Connecticut is politically divided into 8 counties - Fairfield, Hartford, Litchfield, Middlesex, New Haven, New London, Tolland, and Windham. Below the county level, the entire state is divided into 169 incorporated towns and cities, there is no unincorporated land. Typically within the boundaries of an incorporated town or city is a population center with the same name as the incorporated one, such as the town and village of East Haddam. There are also other named population centers within incorporated towns/cities that are sometimes more populated than the village with the incorporated town name, such as Falls Village in the town of Canaan, or Willimantic in the town of Windham. A few of these have established boundaries. Villages and other geographic places within an incorporated town/city typically serve as a more precise reference to a mineral locality. But in some cases there is a village with the same name as a different incorporated town. For example, the village of Canaan is in the incorporated town of North Canaan not the incorporated town of Canaan. Both of these towns include many mineral localities that if just referred to as Canaan would cause confusion.
All Connecticut localities listed in mindat.org should include:
- the name(s) of the locality
- (optional) the closest city or village or other place name (if relevant or different from the incorporated town/city) (USGS maps are a good reference)
- the name of the incorporated town/city (1 of 169)
- the county name

Geology:
Connecticut has a long and complex geologic history that resulted in the presence of many types of sedimentary, igneous, metamorphic and hydrothermal rocks. There are three primary bedrock geologic regions that are part of the continental scale Appalachian Orogen:

1) Metamorphic and igneous rocks of the Western highlands.
2) Sedimentary and igneous rocks of the Central Lowlands (the Hartford Mesozoic Basin of the Newark Terrane).
3) Metamorphic and igneous rocks of the Eastern Highlands.

Within the Western Highlands the metamorphic rocks occur in three major tectonic terranes:

1) Mesoproterozoic massifs (mostly ortho and paragneisses, migmatites and amphibolites) with Neoproterozoic and Cambro-Ordovician quartzite, gneiss, schist and marble shelf sequences (Laurentian continental margin deposits), including the goethite iron ore deposits formed from metamorphosed lateritic soil. These are exposed in westernmost Connecticut and in the core of the Waterbury Dome.
2) Allochthonous Taconian (Hoosic, Manhattan and Canaan Mountain) schist and amphibolite - (Neoproterozoic and Cambrian continental slope deposits), exposed also in westernmost Connecticut.
3) Allochthonous Connecticut Valley Synclinorium and Milford-Orange Terranes (oceanic terranes consisting mostly of Cambrian to Silurian schist and granofels, and intruded by gneissic syntectonic plutons). Parts of these terranes are unconformably capped by Devonian/early Silurian The Straits Schist and Wepawaug Schist. This belt lies in the eastern and southern parts of the Western Highlands.

The Mesoproterozoic massifs underwent metamorphism during the Ottowan phase (approx. 1.05 Ga) of the Grenville Orogeny. These rocks, their Neoproterozoic to Ordovician cover, and the terranes to their east also were deformed by the Taconian and Acadian Orogenies.

Within the Western highlands there are also a few large post-tectonic plutons such as the very late Devonian Nonewaug Granite (and associated pegmatites) and Permian Pinewood Adamellite; numerous small Devonian pegmatites; and the Mesozoic Pomperaug Basin with similar sedimentary and igneous rocks as the much larger Mesozoic Hartford Basin.

The Mesozoic Hartford Basin, part of the Newark Terrane of rift basins formed during the Triassic-Jurassic breakup of Pangaea, underlies the Central Lowlands of Connecticut. It is a continental graben filled with 8-10 km of clastics - arkosic conglomerates, sandstones and mudstones with minor carbonate and petroleum-rich lacustrian shales - three basalt lava flows (including the much-quarried Jurassic Holyoke Basalt), and numerous diabase plutons (principally the Jurassic West Rock Diabase) that also extent into the adjacent highlands.

Within the Eastern Highlands the metamorphic rocks occur in six major tectonic terranes:

1) The Bronson Hill Anticlinorium, which consists of metamorphosed felsic plutons and volcanics of an Ordovician island arc. Part of this terrane is unconformably capped by Devonian/Silurian Bolton Group meta-sediments. This terrane underlies the western part of the Eastern Highlands.
2, 3) Allochthonous Merrimack and Central Maine Terranes (oceanic terranes consisting mostly of Ordovician to Devonian schist, siliceous and calc-silicate gneiss and granofels, and intruded by gneissic syntectonic plutons). These terranes are exposed in the central part of the eastern highlands.
4) Putnam-Nashoba island arc terrane consisting mostly of Ordovician orthogneisses and exposed in far eastern Connecticut and in the Willimantic Dome.
5, 6) Avalon and Gander (Stony Creek, Clinton and Lyme Domes) continental terranes consisting of Neoproterozoic gray ortho and paragneisses, quartzite, meta-granites and alaskite. The Gander Lyme Dome also includes Permian alaskite gneiss. These terranes are intruded by numerous small, post-tectonic plutons of Permian Westerly (or Narragansett Pier) granite and pegmatite. These terranes crop out along the southeastern and eastern edges of the state, and in the Willimantic Dome.

Numerous small to large very early Permian pegmatites intrude the Eastern Highlands terranes, particularly in the area east of Middletown known as the Middletown Pegmatite District.

Ductile faulting on a continental scale has greatly affected the metamorphic and igneous rocks of the Western and Eastern Highlands. Barrovian metamorphism extends from low grade (Chlorite Zone) to high grade (Sillimanite Zone), there is very little contact metamorphism (mostly around the Litchfield Norite) though there is retrograde metamorphism in many areas. Despite the extensive tectonic history, there are only a few remnants of lower oceanic igneous crust; serpentinized fragments of these are found mainly in the Satan's Kingdom area and Orange-Milford Belt.

Brittle faulting associated with the Triassic-Jurassic breakup of Pangaea affected all of Connecticut. Numerous, regional faults are mapped in the Eastern and Western Highlands and, of course, within, bordering and cross-cutting the Hartford and Pomperaug Mesozoic Basins, which formed during this time. Intense brittle faulting is particularly well exposed in the New Britain-Newington area where faults are present every few meters. Many faults and even fractures are mineralized due to hydrothermal activity, the most prominent example being the Lantern Hill quartz lode in North Stonington.

Although late Cretaceous and Tertiary transgressive sediments of the Coastal Plains of eastern North America did cover part of Connecticut, erosion has removed them. Pleistocene glaciation affected the state and deposited extensive till, deltaic sands and gravels, and lacustrian silts and clays.

Mineralogy:
Due to its long and complex geologic history, Connecticut boasts a large variety of mineral forming environments and thus a long list of mineral species. The presence of these deposits so close to major colleges and universities such as Yale, Harvard, Wesleyan, Amherst, and University of Connecticut provided specimens for study by early luminaries such as Archibald Bruce, Benjamin Silliman, Edward Dana, James Dana, George Brush, Wilbur Foye, and Charles Shepard and more recently David London. Mineral specimens from Connecticut are in the museum collections at Greenwich, Middletown, New Haven, and Kent, Connecticut; plus Cambridge and Amherst, Massachusetts; New York City; Washington, DC and beyond. It also created and continues to inspire a plethora of amateur collectors, mostly as hobbyists but also many who have made major contributions (through publications and collections) to the knowledge of the state's mines and minerals, such as Ronald Januzzi, Richard Schooner, Neal Yedlin, Charles and Marcelle Weber, Bill Shelton, John (Jack) Pawloski, Bruce Jarnot, John Hiller, Earle Sullivan, Ed Force, Bob Jones and many others.

The minerals of Connecticut can best be generally categorized by their host rock types and environments listed below.

Igneous Rock Minerals:
- Rock forming minerals in large plutons - albite, microcline/orthoclase, quartz, biotite series, muscovite, dark amphiboles, dark pyroxenes.
- Accessory minerals in large plutons - almandine, fluorapatite, titanite, zircon, rutile, allanite, monazite, schorl, pyrite.
- Rock forming minerals in basalt and diabase - anorthite, augite, pigeonite, olivine.
- Pegmatite minerals - albite (including cleavelandite), microcline, quartz, muscovite, annite, almandine, tourmalines, beryl, fluorapatite, columbite-tantalite, samarskite, uraninite (and secondaries), monazite, zircon, montebrasite, lepidolite, spodumene (and alterations), lithiophilite-triphyllite (and alterations), microlite, cookeite, topaz, opal-AN, pollucite, calcite, fluorite, sulfides, numerous other secondary and rare minerals.

Metamorphic Rock Minerals:
- Rock forming minerals in siliceous schist, gneiss, and amphibolite - albite, quartz, muscovite, biotite series, chlorite series, microcline, dark amphiboles, dark pyroxenes.
- Accessory minerals in siliceous schist, gneiss, and amphibolite - chlorite group, almandine, kyanite, sillimanite, andalusite, ilmenite, fluorapatite, staurolite, cordierite, graphite, rutile, goethite, schorl, titanite, corundum, magnetite, monazite, epidote/clinozoisite, scheelite, ferberite, sulfides.
- Rock forming minerals in marble and calc-silicate rocks - calcite, dolomite, diopside, tremolite, grossular, scapolite series, albite, phlogopite.
- Accessory minerals in marble and calc-silicate rocks - dravite-uvite, pyrite, pyrrhotite, chalcopyrite, graphite, norbergite-chondrodite, titanite, spinel/magnetite, fluorapatite, corundum, quartz, chlorite series, talc, serpentine group, wollastonite, vesuvianite, epidote/clinozoisite/zoisite, microcline, axinite, forsterite, danburite.
- Minerals in serpentinites - serpentine (antigorite, lizardite, chrysotile), talc, pyrophyllite, chlorite series, calcite, tremolite, diopside, epidote/clinozoisite, magnetite, chromite, sulfides (including secondaries).

Sedimentary Rock Minerals:
Mostly clastics consisting of fragments of quartz, feldspars and other rock types, typically cemented by albite with a small amount of hematite, chlorites, and zeolites. The bituminous lacustrian shales include pyrite and nodules of magnesite and there are rare tufa deposits composed of calcite.

Hydrothermal Minerals:
- Minerals in gas vesicles in basalt and diabase - calcite, quartz/chalcedony/agate, datolite, prehnite, pectolite, apophyllite, pumpellyite, julgoldite, babingtonite, adularia, gypsum, anhydrite, celestine, goethite, hematite, sulfides, zeolites (stilbite, heulandite, natrolite, analcime, laumontite, gmelinite, chabazite, mordenite).
- Minerals in faults and fractures - quartz, calcite, dolomite, fluorite, barite, aragonite, siderite, sulfides (pyrite, chalcopyrite, galena, arsenopyrite, chalcocite, bornite) and secondaries, topaz, muscovite, prehnite, pectolite, goethite, hematite, zeolites.

Mining and Quarrying:
All of the above rock types and mineral deposits have been exploited by thousands of open quarries, underground mines, and prospects, studied by geologists and mineralogists, and combed over by collectors. Although Native Americans are known to have worked quartz, talc and serpentinite deposits, the arrival of Europeans and Africans beginning in the early 17th century saw greatly increasing demand for geologic resources.

Besides rock quarrying all over the state for construction purposes, marble deposits were worked for quicklime, particularly in the marble belt in the western part of the Western Highlands. This resource is still in great demand for a variety of purposes and was also mined during WWII for dolomite (magnesium) for aircraft production and the Manhattan Project. Marble quarries are still active in Canaan and North Canaan.

"Granite", mostly actually metamorphosed plutons or meta-volcanic gneisses but also including true Westerly (or Narragansett Pier) granite, was in great demand for construction of expanding towns and cities, and for fortifications starting in the early 19th century, until largely replaced by concrete in the early 20th century. Granite quarrying still takes place in Stony Creek (Branford) and Roxbury.

To produce all that concrete, many quarries worked the diabase and basalt in both the Hartford and Pomperaug Basins for crushed stone. Others work massive gneissic rock in the highlands. Several very large quarries are still active in the Holyoke Basalt, particularly in Southbury/Woodbury, North Branford, Wallingford/Durham, Plainville, Meriden and East Granby. These quarries represent the major mining taking place in Connecticut today. The basalt quarries, and various construction sites that blasted open this rock, sometimes opened up fantastically mineralized gas vesicles and fractures.

"Brownstone", primarily an aeolian arkosic sandstone found in the Jurassic Portland Formation of the Hartford Basin, was heavily quarried for building stone until the early 20th century, particularly at Portland and Manchester. Minor brownstone quarrying took place in Portland from the early 1990s until 2012.

Quarrying and mining for minerals concentrated on three major resources: iron from goethite and siderite; feldspar and mica from pegmatites; and baryte, quartz, and metal ores from hydrothermal veins. The majority of this activity was economically successful, except most of the mining of metal ores from hydrothermal veins. The tungsten mine in Trumbull worked accessory scheelite and ferberite in an amphibolite, but was also not successful. Nor was the cobalt-nickel mining near Great Hill in East Hampton that, like Trumbull, worked a stratigraphic deposit rather than a hydrothermal vein. Pentlandite, chalcopyrite and pyrrhotite grains in the Litchfield Norite is another non-hydrothermal metal deposit that saw failed attempts at profitable mining.

The goethite iron ores mostly originated as lateritic soil formed on an unconformity between the Stockbridge Marble and Walloomsac Schist that was preserved and later metamorphosed. This stratigraphic horizon crops out in a belt largely in Salisbury where it was mined for iron in several places from the early 18th century until 1923. Known for its toughness, Salisbury iron was in great demand for cannon, chains, anchors, and railroad wheels. The Kent mine worked geothite formed in the stratigraphically lower Cambrian Dalton Formation. Here, and at a location in Sharon where it was mined, part of the Dalton was weathered to kaolinite. Another 19th century iron mine operated on Mine Hill in Roxbury exploiting the siderite vein there, which is the largest in North America.

Microcline, muscovite and other minerals were quarried and mined from the numerous pegmatites from about 1825 until 1990. There are hundreds of pegmatite quarries, mostly in the Middletown District in the Eastern Highlands, but also scattered around the Western Highlands such as at Bethel, Ridgefield, Branchville, New Milford, and Woodbury. A burst of pegmatite mining activity took place during and after WWII when sheet mica was in great demand, and for uranium and beryllium for nuclear weapons and power. A by-product of this activity was the production of a plethora of rare and gem minerals that were used for scientific and lapidary purposes and that are still sought after by collectors. Connecticut pegmatites host 9 of the state's 15 type locality minerals or varieties as well as the first known columbite crystal. Some of the first radiometric dating of minerals used uraninite and samarskite from Branchville and Glastonbury. The Roebling quarry, Gillette quarry and Strickland pegmatite were major gem producers, particularly for colored tourmalines and beryl. Most pegmatite quarries closed after the federal subsidies for beryl and mica ended in the 1950s because the high grading of ore was largely done manually. But The Feldspar Corp. operated the state’s largest pegmatite quarries in the White Rock area of Middletown (plus the Hale and Gotta-Wannerstrom quarries in Portland) from about 1960 to 1990 using efficient floatation technology to separate the minerals from vast quantities of crushed ore.

Although not a pegmatite quarry, the quarry for the reservoir dam at East Morris worked an outlier of the Devonian Nonewaug granite and intersected numerous, large miarolitic cavities in pegmatitic phases of the granite. The cavities produced great smoky quartz and microcline crystals with albite similar in quality and size to those from granite plutons in northern New Hampshire.

Finally, the hydrothermal veins so plentiful from the Triassic-Jurassic rifting of Pangaea were exploited for a variety of minerals, primarily quartz at the giant lode at Lantern Hill and other places. Many smaller faults, particularly those cross-cutting quartzite in the highlands, are brecciated with open spaces lined with fantastic quartz crystals, such as at West Stafford, Haddam, Moosup, and Avon. Amethyst occurs at the Canton Lead Mine in Canton. The hydrothermal veins were also worked mainly for copper and baryte during the 19th century. Baryte was successfully mined in Cheshire and copper mining was moderately successful at the Simsbury Mine (the first chartered copper mine in North America) in what is now East Granby, and at the Bristol Copper Mine, famous for its fantastic chalcocite and bornite crystals. There are many small holes and shafts dug by prospectors in search of silver, lead, copper, cobalt, nickel, and the elusive gold, none of which really panned out but now provide places for mineral collectors to ply their trade.

Coordinates are at the intersection of Interstates 91 and 691, state Routes 15 and 66, and East Main Street in Meriden very near the geographic center of the state.
References covering the state, or significant regions of it, are listed below.

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Commodity List

This is a list of exploitable or exploited mineral commodities recorded from this region.


Mineral List

Mineral list contains entries from the region specified including sub-localities

363 valid minerals. 14 (TL) - type locality of valid minerals. 1 (FRL) - first recorded locality of unapproved mineral/variety/etc. 21 erroneous literature entries.

Rock Types Recorded

Note: this is a very new system on mindat.org and data is currently VERY limited. Please bear with us while we work towards adding this information!

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Alphabetical List Tree Diagram

Detailed Mineral List:

Acanthite
Formula: Ag2S
Actinolite
Formula: ☐{Ca2}{Mg4.5-2.5Fe0.5-2.5}(Si8O22)(OH)2
Localities: Reported from at least 42 localities in this region.
Aegirine
Formula: NaFe3+Si2O6
Aegirine-augite
Formula: (NaaCabFe2+cMgd)(Fe3+eAlfFe2+gMgh)Si2O6
Reference: Alkaline Rocks and Carboratites of the World Part I, North and South America,1987,Wolley, A,R,
'Aeschynite'
Description: now equivalent to Davidite-(La)
Reference: Januzzi, R.E. and Seaman, David M. (1976) Mineral Localities Of Connecticut and Southern New York State and Pegmatite Minerals of the World.
'Albertite'
Albite
Formula: Na(AlSi3O8)
Localities: Reported from at least 183 localities in this region.
Albite var: Andesine
Formula: (Na,Ca)[Al(Si,Al)Si2O8]
Localities: Reported from at least 6 localities in this region.
Albite var: Cleavelandite
Formula: Na(AlSi3O8)
Localities: Reported from at least 21 localities in this region.
Albite var: Oligoclase
Formula: (Na,Ca)[Al(Si,Al)Si2O8]
Localities: Reported from at least 22 localities in this region.
Albite var: Peristerite
Formula: Na(AlSi3O8)
Reference: Rocks & Minerals (1995) 70:396-409
'Albite-Anorthite Series'
Localities: Reported from at least 9 localities in this region.
'Alkali Feldspar'
Reference: Philpotts, Anthony R. and Doreen E. Philpotts. (2007), Upward and downward flow in a camptonite dike as recorded by deformed vesicles and the anisotropy of magnetic susceptibility (AMS). Journal of Volcanology and Geothermal Research: 161: 81-94.
Allanite-(Ce)
Formula: {CaCe}{Al2Fe2+}(Si2O7)(SiO4)O(OH)
Localities: Reported from at least 6 localities in this region.
'Allanite Group'
Formula: {A12+REE3+}{M3+2M32+}(Si2O7)(SiO4)O(OH)
Localities: Reported from at least 18 localities in this region.
Alleghanyite
Formula: Mn2+5(SiO4)2(OH)2
Colour: reddish
Description: Found by Dick Schooner. A segregation over a foot in diameter, it consisted mainly of reddish alleghanyite and pinkish kutnohorite, with accessories. Unfortunately, only a few specimens were saved.
Reference: Schooner, Richard. (circa 1980s), Untitled manuscript on central Connecticut minerals.
Allophane
Formula: (Al2O3)(SiO2)1.3-2 · 2.5-3H2O
Alluaudite ?
Formula: (Na,Ca)Mn2+(Fe3+,Mn2+,Fe2+,Mg)2(PO4)3
Habit: pseudomorph after triphylite?
Description: From Januzzi (1994): "Alluaudite, collected and recently identified by the author as occurring at Branchville (confirmation by Kampf, Los Angeles County Museum of Natural History), is evidently a pseudomorph after euhedral crystals of triphylite." Needs confirmation.
Reference: Januzzi, Ronald. E. (1994): Mineral Data Book - Western Connecticut and Environs. Mineralogical Press, Danbury, Connecticut.
Almandine
Formula: Fe2+3Al2(SiO4)3
Localities: Reported from at least 119 localities in this region.
'Almandine-Spessartine Series'
'Alum Group'
Formula: XAl(SO4)2 · 12H2O
Amblygonite
Formula: LiAl(PO4)F
'Amphibole Supergroup'
Formula: AX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
Localities: Reported from at least 9 localities in this region.
'Amphibole Supergroup var: Byssolite'
Formula: AX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
'Amphibole Supergroup var: Uralite' ?
Formula: AX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2
Description: Included in a list of minerals with no details.
Reference: Januzzi, Ronald E. (1976): Mineral Localities of Connecticut and Southeastern New York State. The Mineralogical Press, Danbury, Connecticut: 192-201.
Analcime
Formula: Na(AlSi2O6) · H2O
Localities: Reported from at least 13 localities in this region.
Anatase
Formula: TiO2
Localities: Reported from at least 15 localities in this region.
Andalusite
Formula: Al2(SiO4)O
Andradite
Formula: Ca3Fe3+2(SiO4)3
Andradite var: Melanite
Formula: Ca3Fe3+2(SiO4)3
Habit: rhombic dodecahedral, often in nearly parallel positions in rosettes
Colour: dark-brown to jet-black, occasionally yellowish-brown
Description: Rosettes reach to about 2 cm across.
Reference: Dana, Edward S. (1877): On the occurrence of Garnets with the Trap of New Haven, Connecticut. American Journal of Science Series 3, Volume 14, page 215.
Andradite var: Topazolite
Formula: Ca3Fe3+2(SiO4)3
Habit: modified rhombic dodecahedrons
Colour: wine yellow
Description: "The Mill Rock garnets have a wine-yellow color, and a brilliant luster. The material available was much too scanty to admit of any chemical examination, but in view of their similarity of form and color, they may safely be referred to the variety topazolite." (Dana, 1877). They are a couple of mm across or less. Visual ID only, material too scant for analysis back then.
Reference: Dana, Edward S. (1877): On the occurrence of Garnets with the Trap of New Haven, Connecticut. American Journal of Science Series 3, Volume 14, page 215.; Longwell & Dana, 1932. Walks & Rides in Central CT & MA, p.228.
Anglesite
Formula: PbSO4
Localities: Reported from at least 9 localities in this region.
Anhydrite
Formula: CaSO4
Localities: Reported from at least 22 localities in this region.
Ankerite
Formula: Ca(Fe2+,Mg)(CO3)2
Habit: rhombohedral
Description: Typical small rhombs <1 cm. Uncertain in the reference if the crystals are true ankerite under the revised definition, or ferroan dolomite, or how to distinguish them from the much more common magnesite.
Reference: Ague, J. J. (1995): Deep Crustal Growth of Quartz, Kyanite and Garnet into Large-Aperature, fluid-filled fractures, northeastern Connecticut, USA. Journal of Metamorphic Geology: 13: 299-314.
Annabergite
Formula: Ni3(AsO4)2 · 8H2O
Habit: coatings
Colour: bright to pale green
Description: waxy, pale to bright green coatings on ore-bearing host rocks, particularly around bronze nickeline grains.
Reference: Schooner (1958); Januzzi (1976) Mineral Localities of Connecticut & Southeastern New York State
Annite
Formula: KFe2+3(AlSi3O10)(OH)2
Localities: Reported from at least 62 localities in this region.
Anorthite
Formula: Ca(Al2Si2O8)
Localities: Reported from at least 6 localities in this region.
Anorthite var: Bytownite
Formula: (Ca,Na)[Al(Al,Si)Si2O8]
Reference: Januzzi, 1976. Mineral Localities of CT and Southeastern NY State
Anorthite var: Labradorite
Formula: (Ca,Na)[Al(Al,Si)Si2O8]
Anthophyllite
Formula: ☐{Mg2}{Mg5}(Si8O22)(OH)2
Localities: Reported from at least 9 localities in this region.
Antigorite
Formula: Mg3(Si2O5)(OH)4
Antimony ?
Formula: Sb
Habit: broad plates
Description: Reference notes that the validity needs confirmation, but this was apparently either not done of found to be something else (ilmenite?).
Reference: Hitchcock, Edward. (1823). A Sketch of the Geology, Mineralogy, and Scenery of the Regions Contiguous to the River Connecticut. American Journal of Science, s. 1, vol. 6, no. 2, p. 235.
'Apatite'
Formula: Ca5(PO4)3(Cl/F/OH)
Localities: Reported from at least 23 localities in this region.
'Apophyllite'
Localities: Reported from at least 16 localities in this region.
Aragonite
Formula: CaCO3
Localities: Reported from at least 33 localities in this region.
Arrojadite-(KFe) ?
Formula: {KNa}{Fe2+◻}{Ca}{Na2◻}{Fe2+13}{Al}(PO4)11(HPO4)(OH)2
Description: reported by Dick Schooner, no details in the reference.
Reference: Januzzi (1976) p.234-5.
Arsenic ?
Formula: As
Arsenolite ?
Formula: As2O3
Arsenopyrite
Formula: FeAsS
Localities: Reported from at least 25 localities in this region.
Arsenopyrite var: Danaite
Formula: (Fe0.90Co0.10)AsS - (Fe0.65Co0.35)AsS
Habit: massive, striated aggregates
Description: The arsenopyrite is not the Co-Ni ore, earlier references to and analyses of "danaite" are probably from confusion with the loellingite ore veins.
Reference: Shannon (1921); Gray (2005)
'Asbestos'
'Asbestos var: Mountain Leather'
Habit: fibrous
Colour: white
Description: Fairly thick, white, matted fibers of amphibole or perhaps sepiolite.
Reference: Januzzi, Ronald E. (1976), Mineral Localities of Connecticut and Southeastern New York State. The Mineralogical Press, Danbury, Connecticut.
Atacamite
Formula: Cu2(OH)3Cl
Habit: micro radiating clusters, aggregates, druses
Colour: deep green, sky blue
Description: Henderson (1967) reports: deep green crystals of quite variable habit up to 0.5 mm in size. The terminal planes of single crystals were generally bright, while faces in the prism zone were rounded and striated (Fig. 3). It also occurred as radiating groups and in irregular aggregates, sometimes with a single larger crystal perched on top. Druses of atacamite on vesicles were common. It was most frequently found close to or on cuprite, but occasionally appeared to be on malachite. Identification was based on its solubility in dilute hydrochloric and nitric acids, a positive test for halogen, and negative tests for carbonate and sulfate. The atacamite showed parallel extinction and weak birefringence, the two together ruling our malachite, antlerite and brochantite. The mineral was distinguished from paratacamite by its crystal form. On occasion, crystals corresponding to atacamite were found but with a sky blue color. These may well be pseudomorphs of rosasite after atacamite.
Reference: Henderson, William, A., Jr. (1967), A Copper Analog of Laurium, Greece. Rocks & Minerals: 42(5): 273-276.
Augelite
Formula: Al2(PO4)(OH)3
Augite
Formula: (CaxMgyFez)(Mgy1Fez1)Si2O6
Localities: Reported from at least 13 localities in this region.
Augite var: Fassaite
Formula: (Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6]
Augite var: Titanian Augite
Formula: (Ca,Na)(Mg,Ti, Fe,Al,)(Si,Al)2O6
Reference: Philpotts, Anthony R. and Doreen E. Philpotts. (2007), Upward and downward flow in a camptonite dike as recorded by deformed vesicles and the anisotropy of magnetic susceptibility (AMS). Journal of Volcanology and Geothermal Research: 161: 81-94.
Aurichalcite
Formula: (Zn,Cu)5(CO3)2(OH)6
Localities: Reported from at least 6 localities in this region.
Autunite
Formula: Ca(UO2)2(PO4)2 · 11H2O
Localities: Reported from at least 27 localities in this region.
Axinite-(Fe)
Formula: Ca2Fe2+Al2BSi4O15OH
'Axinite Group' ?
Azurite
Formula: Cu3(CO3)2(OH)2
Localities: Reported from at least 16 localities in this region.
Babingtonite
Formula: Ca2(Fe,Mn)FeSi5O14(OH)
Localities: Reported from at least 14 localities in this region.
Baryte
Formula: BaSO4
Localities: Reported from at least 37 localities in this region.
Bastnäsite-(Ce)
Formula: Ce(CO3)F
Habit: thin, irregular plates
Colour: brown, reddish-brown to yellowish-tan
Description: Irregular thin plates, as much as two or three inches across and a half of an inch thick, are intimately associated with massive allanite, white to greenish plagioclase, pink to purple fluorite, chalcopyrite and pyrite. Some may be altered to gray lanthanite?
Reference: Weber, Marcelle H. and Earle C. Sullivan. (1995): CONNECTICUT MINERAL LOCALITY INDEX. Rocks & Minerals (Connecticut Issue), Volume 70, No. 6, p. 403.; Schooner, Richard. (1958): The Mineralogy of the Portland-East Hampton-Middletown-Haddam Area in Connecticut (With a few notes on Glastonbury and Marlborough).; Schooner, Richard. (1961): THE MINERALOGY OF CONNECTICUT.
Bavenite
Formula: Ca4Be2Al2Si9O26(OH)2
Bazzite
Formula: Be3Sc2(Si6O18)
Reference: From Richard Schooner collection, now int he Anthony J. Albini collection, personally collected by Richard and analyzed.
Becquerelite
Formula: Ca(UO2)6O4(OH)6 · 8H2O
Habit: pseudomorphs after uraninite
Colour: yellow
Description: "A soft yellow pseudomorph after a uraninite crystal was X-rayed, and proved to be becquerelite." Schooner (circa 1980s).
Reference: Januzzi, R.E. (1976): Mineral Localities Of Connecticut and Southern New York State. p.234.; Schooner, Richard. (circa 1980s), Untitled manuscript on central Connecticut mineralogy.
Bementite ?
Formula: Mn7Si6O15(OH)8
Beraunite
Formula: Fe2+Fe3+5(PO4)4(OH)5 · 6H2O
Bertrandite
Formula: Be4(Si2O7)(OH)2
Localities: Reported from at least 29 localities in this region.
Beryl
Formula: Be3Al2(Si6O18)
Localities: Reported from at least 109 localities in this region.
Beryl var: Aquamarine
Formula: Be3Al2Si6O18
Localities: Reported from at least 19 localities in this region.
Beryl var: Emerald
Formula: Be3Al2(Si6O18)
Beryl var: Goshenite
Formula: Be3Al2(Si6O18)
Localities: Reported from at least 6 localities in this region.
Beryl var: Heliodor
Formula: Be3Al2(Si6O18)
Localities: Reported from at least 14 localities in this region.
Beryl var: Morganite
Formula: Be3Al2(Si6O18)
Localities: Reported from at least 11 localities in this region.
Beyerite ?
Formula: Ca(BiO)2(CO3)2
Description: Reference includes a list of minerals reportedly found by Dick Schooner in a pegmatite in East Hampton, but with no supporting details.
Reference: Januzzi, 1976. Mineral Localities of CT & SE NY State
'Biotite'
Formula: K(Fe2+/Mg)2(Al/Fe3+/Mg)([Si/Al]Si2O10)(OH/F)2
Localities: Reported from at least 61 localities in this region.
Birnessite
Formula: (Na,Ca)0.5(Mn4+,Mn3+)2O4 · 1.5H2O
Habit: encrustation
Colour: black
Description: "This is one of the manganese oxides identified as a component of the soft black alteration crusts on tephroite, etc."
Reference: Schooner, Richard. (circa 1980s), Untitled manuscript on central Connecticut minerals.
Bismite
Formula: Bi2O3
Bismuth
Formula: Bi
Localities: Reported from at least 9 localities in this region.
Bismuthinite
Formula: Bi2S3
Localities: Reported from at least 20 localities in this region.
Bismutite
Formula: (BiO)2CO3
Localities: Reported from at least 20 localities in this region.
Bismutoferrite
Formula: Fe3+2Bi(SiO4)2(OH)
Habit: massive coatings
Colour: green
Description: Associated with bismuthinite and pyrite with secondary bismite, bismutite (some or all may in fact be bismutoferrite) and goethite staining pegmatite matrix.
Reference: Huff, R. C., R. G. Huff, J. Vajdak. (1996), An Occurrence of Bismutoferrite in Portland, Connecticut. Rocks & Minerals: 71(3): 197.; Vajdak, Josef. (1997), New Mineral Finds in 1996, News from Vajdak of Pequa Rare Minerals and Metals. Mineral News: 13:(3): 1,4,5.
Bismutotantalite
Formula: Bi(Ta,Nb)O4
Habit: anhedral
Colour: gray exterior, brown interior
Description: Very small grains to a couple of mm in matrix of albite, muscovite, quartz, elbaite. Analyzed in 2017 by Peter Cristofono and Tom Mortimer.
Reference: Eric Briggs collection
'Bitumen'
Localities: Reported from at least 16 localities in this region.
Bityite
Formula: LiCaAl2(AlBeSi2O10)(OH)2
Habit: hexagonal
Colour: white
Description: Schooner (circa 1985) says: "When the Strickland quarry was last active, the author found a boulder of cleavelandite with a small vug of aggregated lustrous white hexagonal-looking crystals with calcite and a trace of lepidolite. It was many years before the mineral was recognized as being a mica! Its unusual X-ray pattern aroused some curiosity, and it was forwarded to Pete J. Dunn at the Smithsonian. He identified it as bityite, and made an analysis by electron microprobe."
Reference: Schooner, Richard. (circa 1985), Untitled manuscript on central Connecticut mineralogy.
'Bloodstone'
Formula: SiO2
Colour: shades of red
Description: Found as loose rocks in glacial till.
Reference: Orcutt, Rev. Samuel. (1878), History of Torrington, Connecticut. J. Munsell, Albany: 174-179.
Bornite
Formula: Cu5FeS4
Localities: Reported from at least 21 localities in this region.
Brazilianite
Formula: NaAl3(PO4)2(OH)4
Breithauptite ?
Formula: NiSb
'Brewsterite' ?
Brochantite
Formula: Cu4(SO4)(OH)6
Reference: Jeremy Zolan Collecton- Specimens Identified by wet chemistry, 2/26/2007.
Brookite
Formula: TiO2
Localities: Reported from at least 6 localities in this region.
Brucite ?
Formula: Mg(OH)2
Colour: whitish green
Description: "Amianthus is sometimes nearly as fine as that of Corsica." (Robinson 1825). Uncertain if he was referring to brucite or byssolite.
Reference: Robinson (1825)
Bustamite
Formula: CaMn2+(Si2O6)
Habit: cleavable masses
Colour: light pink
Description: When the author discovered a large lens of spessartine at the Jail Hill quarry, in the 1950s, a few good specimens of pink "rhodonite" were collected. Two different shades were associated differently, one with spessartine and calcite (or dolomite), the other with tephroite and pyrophanite. X-ray and spectrographic tests have shown the lighter pink mineral to be bustamite, and the darker one pyroxmangite. In some cases, bustamite is intimately intergrown with johannsenite (probably an exsolution product).
Reference: Schooner, Richard. (circa 1980s), Untitled manuscript on central Connecticut minerals.
'Calamine'
Reference: Gems and Minerals of America -Jay Ellis Ransom-1974
'Calciomicrolite'
Colour: brown
Description: A single 21mm fragment was analyzed via SEM-EDS and best match is calciomicrolite. Whether this is characteristic of all the abundant micro-crystals posted as "microlite" is uncertain. Zones within it were also analyzed and showed a Ca-Ta oxide with minor Nb (and no Na or Ti)...this could also be microlite, or perhaps calciotantite, which can occur as an inclusion in microlite.
Reference: Adam Berluti collection
Calcite
Formula: CaCO3
Localities: Reported from at least 146 localities in this region.
Calcite var: Ferroan Calcite
Formula: (Ca,Fe)CO3
Reference: Rocks & Minerals. Vol. 70. No. 6
Carnotite
Formula: K2(UO2)2(VO4)2 · 3H2O
Reference: Gray 1982
Caryopilite
Formula: Mn2+3Si2O5(OH)4
Description: This was identified (at the University of Michigan) as a very minor component of "ore" from the manganese pod at the Jail Hill quarry in Haddam.
Reference: Schooner, Richard. (circa 1980s), Untitled manuscript on central Connecticut minerals.
Cassiterite
Formula: SnO2
Localities: Reported from at least 7 localities in this region.
Celadonite
Formula: K(Mg,Fe2+)Fe3+(Si4O10)(OH)2
Celestine
Formula: SrSO4
Cerite-(Ce) ?
Formula: (Ce,Ca)9(Mg,Fe)(SiO4)3(HSiO4)4(OH)3
Description: Reference includes a list of minerals reportedly found by Dick Schooner in a pegmatite in East Hampton, but with no supporting details.
Reference: Januzzi, 1976. Mineral Localities of CT and Southeastern NY State, p.234
Cerussite
Formula: PbCO3
Localities: Reported from at least 15 localities in this region.
'Chabazite'
Localities: Reported from at least 26 localities in this region.
'Chabazite var: Phacolite'
Reference: Kevin Czaja Collection, Ex: Marcelle Weber Coll: m1236
Chabazite-Ca
Formula: (Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
Localities: Reported from at least 9 localities in this region.
Chalcanthite
Formula: CuSO4 · 5H2O
Chalcocite
Formula: Cu2S
Localities: Reported from at least 15 localities in this region.
'Chalcodite'
Formula: K(Fe3+,Mg,Fe2+)8(Si,Al)12(O,OH)27
Reference: R. Zinderman photo
Chalcopyrite
Formula: CuFeS2
Localities: Reported from at least 98 localities in this region.
Chalcopyrite var: Blister Copper
Formula: CuFeS2
Reference: MinRec 32:433
'Chlorite Group'
Localities: Reported from at least 65 localities in this region.
'Chlorophyllite'
Chondrodite
Formula: (Mg,Fe2+)5(SiO4)2(F,OH)2
Localities: Reported from at least 8 localities in this region.
Chromite
Formula: Fe2+Cr3+2O4
Chrysoberyl
Formula: BeAl2O4
Chrysocolla
Formula: Cu2-xAlx(H2-xSi2O5)(OH)4 · nH2O
Localities: Reported from at least 20 localities in this region.
'Chrysoprase'
Colour: apple green
Description: Found as loose rocks in glacial till.
Reference: Orcutt, Rev. Samuel. (1878), History of Torrington, Connecticut. J. Munsell, Albany: 174-179.
Chrysotile
Formula: Mg3(Si2O5)(OH)4
Localities: Reported from at least 7 localities in this region.
Churchite-(Y)
Formula: Y(PO4) · 2H2O
Habit: colloform with concentric layers
Colour: pale yellow-white
Description: Thin colloform crust on goethite with an associated opal-AN-like layer. In Januzzi (1994) the discoverer states, "Recent examination, by way of x-ray and semi-quantitative analysis uncovered a new species for the Scoville Ore Bed in Salisbury, Connecticut; the mineral churchite, a relatively inconspicuous species and confused (no doubt often) with rhabdophane and probably more common than realized. Florencite should be looked for when churchite occurs in a deposit of this type. A hyalite-like mineral evidently forming before churchite lies just beneath it (the specimen is in the author’s collection)-this species is very possibly evansite."
Reference: Januzzi, Ronald E. (1994), Mineral Data Book. The Mineralogical Press, Danbury.
Claudetite ?
Formula: As2O3
Description: According to an unconfirmed report by Schooner (circa 1980s), associated with arsenopyrite were "a few soft, transparent, gypsum-like plates" of claudetite.
Reference: Schooner, Richard. (circa 1980s), Untitled manuscript on central Connecticut mineralogy.
Clinochlore
Formula: Mg5Al(AlSi3O10)(OH)8
Localities: Reported from at least 23 localities in this region.
Clinochlore var: Diabantite ?
Formula: (Mg,Fe,Al)6((Si,Al)4O10)(OH)8
Colour: Deep green
Description: Filling small cavities, this mineral may actually be pumpellyite, which is now known to be common in the local traprock, but there were few quarries in that rock in 1920.
Reference: Shannon, Earl V. (1920), The Trap Quarry at Meriden, Connecticut. The American Mineralogist: 5(2):34.
Clinochlore var: Ripidolite
Formula: (Mg,Fe,Al)6(Si,Al)4O10(OH)8
Habit: fine anhedral grains
Colour: dark green
Description: Forms fine-grained masses at the contact between the quartz mass and the host schist.
Reference: American Museum of Natural History display
'Clinopyroxene Subgroup'
Clinozoisite
Formula: {Ca2}{Al3}(Si2O7)(SiO4)O(OH)
Localities: Reported from at least 15 localities in this region.
Clinozoisite var: Clinothulite
Formula: {Ca2}{Al3}(Si2O7)(SiO4)O(OH)
Habit: granular
Colour: pink
Description: Granular material in quartz, with calc-silicate minerals in the amphibolite. Clinozoisite is much more common than zoisite and more likely a mineral to occur in this metamorphic terrain.
Reference: Eric Briggs collection
Cobaltite
Formula: CoAsS
Coffinite
Formula: U(SiO4) · nH2O
Reference: Gray 1982
Columbite-(Fe)
Formula: Fe2+Nb2O6
Localities: Reported from at least 24 localities in this region.
'Columbite-(Fe)-Columbite-(Mn) Series'
Localities: Reported from at least 42 localities in this region.
'Columbite Group'
Habit: tabular
Colour: black with iridescence
Description: Subhedral crystals in pegmatite matrix.
Reference: Former Ronald Januzzi collection
'Columbite-Tantalite'
Cookeite
Formula: (Al2Li)Al2(AlSi3O10)(OH)8
Localities: Reported from at least 8 localities in this region.
Copiapite
Formula: Fe2+Fe3+4(SO4)6(OH)2 · 20H2O
'Copiapite Group'
Reference: Kevin Czaja Collection
Copper
Formula: Cu
Localities: Reported from at least 16 localities in this region.
Cordierite
Formula: (Mg,Fe)2Al3(AlSi5O18)
Localities: Reported from at least 14 localities in this region.
Corundum
Formula: Al2O3
Localities: Reported from at least 12 localities in this region.
Corundum var: Sapphire
Formula: Al2O3
Covellite
Formula: CuS
Localities: Reported from at least 6 localities in this region.
Crandallite ?
Formula: CaAl3(PO4)(PO3OH)(OH)6
Description: Schooner (1955) reports it "as microscopic crystals associated with bertrandite" found by Gunnar Bjareby. However, he does not mention it in any of his subsequent writings on the area.
Reference: Schooner, Richard. (1955): 90 Minerals from 1 Connecticut Hill. Rocks & Minerals: 30(7-8): 351-8.
Cronstedtite
Formula: Fe2+2Fe3+((Si,Fe3+)2O5)(OH)4
Cryptomelane
Formula: K(Mn4+7Mn3+)O16
Habit: botryoidal
Colour: black with blue tint
Reference: Harold Moritz collection
Cummingtonite
Formula: ☐{Mg2}{Mg5}(Si8O22)(OH)2
Cuprite
Formula: Cu2O
Localities: Reported from at least 17 localities in this region.
Cuprite var: Chalcotrichite
Formula: Cu2O
Habit: acicular
Reference: Henderson, William, A., Jr. (1967), A Copper Analog of Laurium, Greece. Rocks & Minerals: 42(5): 273-276.
Cuprobismutite
Formula: Cu8AgBi13S24
Habit: massive, coatings
Description: Associated with bismuthinite and pyrite with secondary bismite, bismutite (some or all may in fact be bismutoferrite) and goethite staining pegmatite matrix.
Reference: Vajdak, Josef. (1997), New Mineral Finds in 1996, News from Vajdak of Pequa Rare Minerals and Metals. Mineral News: 13:(3): 1,4,5.
'Cymatolite'
Danburite (TL)
Formula: CaB2Si2O8
Reference: Shepard, C.U. (1939) Amer J of Sci; Shepard, C.U. (1840): Der Danburit, eine neue Mineralspecies, Annalen der Physik und Chemie, Vol. 126 (2/050), p. 182
Datolite
Formula: CaB(SiO4)(OH)
Localities: Reported from at least 34 localities in this region.
Davidite-(La)
Formula: (La,Ce)(Y,U,Fe)(Ti,Fe)20(O,OH)38
Habit: subhedral
Colour: pitch black
Description: Small 1-2 cm obsidian-black subhedral crystals with red staining in adjacent rock.
Reference: Rocks & Min.:64:471.; Rocks & Minerals (1995) 70:396-409
Devilline
Formula: CaCu4(SO4)2(OH)6 · 3H2O
Diadochite
Formula: Fe3+2(PO4)(SO4)(OH) · 5H2O
Habit: coatings and micro globules
Colour: orange
Description: Orange coatings on triphylite, messelite, and other related phosphates
Reference: Schooner (1961); Januzzi (1976) p. 234.
Diamond
Formula: C
Habit: cubic
Colour: grey
Description: Single alluvial crystal 0.8mm
Reference: Jarnot, Bruce and Jarnot, Miranda (2004): "Gem Almandine from Colchester, Connecticut," in: abstracts of the 31st Rochester Mineralogical Symposium, April 15-18, 2004, pp 13-14.
Diaspore
Formula: AlO(OH)
Habit: thin or 6-sided tables flattened parallel to the shorter diagonal
Colour: yellowish-white
Description: First reported by Shepard (1842) as euclase forming "thin, transparent, yellowish-white tabular crystals, lining cavities in a silvery white mica, and sometimes imbedded in a dark purple fluor" in the topaz veins. Later retracted and confirmed to be diaspore by Shepard (1851) and Dana (1851): H=7-7.5, SG=3.29, alumina 84.9%, water 15.1% and described as "thin or 6-sided tables flattened parallel to the shorter diagonal". May be more common than reported because who has really looked?
Reference: Shepard, Charles U. (1842): On Washingtonite (a New Mineral), the Discovery of Euclase in Connecticut, and Additional Notices of the Supposed Phenakite of Goshen, and Calstron-baryte of Schoharie, N. Y. American Journal of Science: 43: 364.; Dana, James D. (1851): Mineralogical Notices: Diaspore. American Journal of Science: s. 2: 12: 215.; Shepard, Charles U. (1851): Title unknown. Proceedings of the 4th Meeting, American Association for the Advancement of Science: 319.
Dickinsonite-(KMnNa) (TL)
Formula: {KNa}{Mn2+◻}{Ca}{Na3}{Mn2+13}{Al}(PO4)12(OH)2
Habit: foliated crystalline masses, almost micaceous, radiating or stellated curved laminae
Colour: oil to olive green, dark to grass-green
Description: Intimately associated with quartz, eosphorite, triploidite and rhodochrosite
Reference: Brush and Dana (1878).; Shainin, V. (1946) The Branchville, Connecticut, Pegmatite. American Mineralogist: 31: 329-345.; Palache, C., Berman, H., & Frondel, C. (1951) The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 671, 718, 855.; Moore, P.B., Ito, J. (1979) Alluaudites, wyllieites, arrojadites: crystal chemistry and nomenclature. Mineralogical Magazine: 43: 227-235.; Weber, Marcelle H. and Earle C. Sullivan (1995) Connecticut Mineral Locality Index. Rocks & Minerals (Connecticut Issue): 70(6) (November/December): 396-409.; Daltry, V.D.C. and von Knorring, O. (1998) Type-mineralogy of Rwanda with particular reference to the Buranga pegmatite. Geologica Belgica: 1: 9-15 (referring to Moore & Ito, 1979).
Dickite
Formula: Al2(Si2O5)(OH)4
Digenite
Formula: Cu9S5
Reference: MinRec 32:433
Diopside
Formula: CaMgSi2O6
Localities: Reported from at least 40 localities in this region.
Diopside var: Canaanite
Formula: CaMgSi2O6
Reference: Schairer, John Frank (1931): The Minerals of Connecticut, State Geological and Natural History Survey Bulletin 51
Djurleite
Formula: Cu31S16
Reference: Harvard Museum of Natural History specimen no. 81791
Dolomite
Formula: CaMg(CO3)2
Localities: Reported from at least 31 localities in this region.
Dolomite var: Ferroan Dolomite
Formula: Ca(Mg,Fe)(CO3)2
Dravite
Formula: Na(Mg3)Al6(Si6O18)(BO3)3(OH)3(OH)
Localities: Reported from at least 9 localities in this region.
Dumortierite ?
Formula: (Al,Fe3+)7(SiO4)3(BO3)O3
Habit: acicular
Colour: bright blue
Description: A few concentrations of tiny acicular crystals in one specimen of coarse-grained albite/quartz/biotite gneiss matrix.
Reference: Former Ronald Januzzi collection
'Elaterite'
Formula: (C,H,O,S)
Reference: Williamson, 1932. Book of Amber, p.254.
Elbaite
Formula: Na(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH)
Localities: Reported from at least 16 localities in this region.
Enstatite
Formula: MgSiO3
Enstatite var: Bronzite
Formula: (Mg,Fe2+)2[SiO3]2
Reference: Meteoritics, vol. 11, June 30, 1976, p. 111-130.
Eosphorite (TL)
Formula: Mn2+Al(PO4)(OH)2 · H2O
Habit: mostly massive, rare prismatic crystals
Colour: pale pink, grayish-, bluish-, and yellowish-white, white
Description: Intimately associated with quartz, dickinsonite, triploidite and rhodochrosite. Pink, translucent, prismatic crystals to around 1 cm long show rough striae parallel to the long axis, associated with micro encrusting quartz and apatite.
Reference: Brush and Dana (1878); American Mineralogist (1946): 31: 329-345; Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 671, 718, 855, 938.; Rocks & Minerals (1995) 70:396-409
Epidote
Formula: {Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
Localities: Reported from at least 55 localities in this region.
Epidote var: Tawmawite
Formula: {Ca2}{(Al,Fe3+,Cr)3}(Si2O7)(SiO4)O(OH)
Description: A completely unsubstantiated guess.
Reference: Januzzi, Ronald E. and David Seaman (1976), Mineral Localities of Connecticut and Southeastern New York State and Pegmatite Minerals of the World. The Mineralogical Press, Danbury, Connecticut.
Epistilbite
Formula: CaAl2Si6O16 · 5H2O
Epsomite
Formula: MgSO4 · 7H2O
Erythrite
Formula: Co3(AsO4)2 · 8H2O
Euclase ?
Formula: BeAl(SiO4)(OH)
Eucryptite (TL)
Formula: LiAlSiO4
Habit: pseudomorphous after spodumene
Colour: white to slightly greenish-white or pale gray
Fluorescence: red
Description: oriented intergrowth with very fine-grained, elongated albite. Grains are oriented perpendicular to the spodumene c axis and give an indistinct fibrous to columnar structure, this being always at right angles to the adjoining surface of the original mineral. Fractured surface typically has a frosty appearance.
Reference: Brush and Dana (1880); AmMin 31:329-345 (1946); USGS Prof Paper 255; Rocks & Minerals (1995) 70:396-409; Ronald Januzzi collection
Euxenite-(Y)
Formula: (Y,Ca,Ce,U,Th)(Nb,Ta,Ti)2O6
Description: Reference by Januzzi (1976) to this mineral being found by Schooner in "Portland" correlates only with a report by Schooner (circa 1985) from the Hale Quarry in Portland. Schooner makes no mention if it from Strickland in his various comprehensive publications, especially his last, Schooner (circa 1985).
Reference: Januzzi, Ronald E. (1976): Mineral Localities of Connecticut and Southeastern New York State (Taylor Assoc./Mineralogical Press): 234-5.
'Fahlunite'
Formula: (Mg,Fe)Al2Si3O10 · 2H2O
Fairfieldite (TL)
Formula: Ca2Mn2+(PO4)2 · 2H2O
Habit: foliated to lamellar masses, radiating masses consisting of curved foliated or fibrous aggregations
Colour: white to pale straw-yellow
Description: One variety cccurs filling cavities in the reddingite, and covering the distinct crystals of this mineral. It is uniformly clear and transparent, and is highly lustrous, showing entire absence of even incipient alteration. It is generally foliated to lamellar, although sometimes of a somewhat radiated structure. A second variety occurs in masses of considerable size interpenetrated rather irregularly with quartz, and quite uniformly run through with thin seams and lines of a black manganesian mineral of not very clearly defined character. Typically friable to the touch and lacks something of the brilliant luster of the first variety, it also shows greater difference of structure, passing from the distinct crystals to the massive and radiated form. Also occurs in small particles in fillowite and in masses of some size immediately associated with eosphorite, triploidite, and dickinsonite.
Reference: Brush and Dana (1878); Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 671, 721; NJMM (1957), 78; Lapis (1984): 2: 5.; Rocks & Minerals (1995) 70:396-409
'Fayalite-Forsterite Series'
Localities: Reported from at least 8 localities in this region.
'Feldspar Group'
Localities: Reported from at least 14 localities in this region.
'Feldspar Group var: Perthite'
Localities: Reported from at least 9 localities in this region.
Ferberite
Formula: FeWO4
'Fergusonite' ?
Ferricopiapite ?
Formula: Fe5(SO4)6O(OH) · 20H2O
Description: Details of the find needed.
Reference: Jeremy Zolan
Ferri-ghoseite
Formula: ☐[Mn2+Na][Mg4Fe3+]Si8O22(OH)2
Habit: lamellar or bladed
Colour: tan or green
Description: Reported by Dick Schooner as "Tirodite", reference below provides no details. An XRD analysis of a sample labeled "tirodite" from Dick Schooner's collection could not differentiate it from actinolite. However, Schooner (circa 1980s) reports: "Tan or green tirodite, lamellar and bladed, was rather common at the Jail Hill quarry, usually with only spessartine or barite. Masses two inches across have been preserved. A few little silky-fibrous tufts proved to be tirodite, also. This material was studied at the University of Michigan."
Reference: Januzzi (1976) p.229, 235; Schooner, Richard. (circa 1980s), Untitled manuscript on central Connecticut minerals.
Ferrimolybdite
Formula: Fe2(MoO4)3 · nH2O
Ferrisicklerite
Formula: Li1-x(Fe3+xFe2+1-x)PO4
'Ferro-Actinolite-Tremolite Series'
Reference: Januzzi, 1976. Mineral Localities of CT and Southeastern NY State; Samuel Robinson (1825) A Catalogue of American Minerals, with their localities. Boston
Ferrosaponite ?
Formula: Ca0.3(Fe2+,Mg,Fe3+)3((Si,Al)4O10)(OH)2 · 4H2O
Habit: micaceous or foliated globules or coatings
Colour: very dark green to black
Description: A late forming, fine-grained, very dark green to black micaceous mineral forming tiny globules or coating other minerals in vesicles in basalt. An SEM-EDS analysis conducted in 2017 concluded the mineral is an Fe-Mg-Ca aluminosilicate. The complete absence of K rules out stilpnomelane, biotite, celadonite. The Ca is too low for pumpellyite or julgoldite. A mindat.org mineral search by chemistry found ferrosaponite as a good match, as are its physical properties and geoenvironment of formation. However, XRD is needed for confirmation.
Reference: Former Bill Barrett collection
Fillowite (TL)
Formula: {Mn2+}{Na8}{Ca4Na4}{(Mn2+,Fe2+)43}(PO4)36
Type Locality:
Habit: granular aggregates, rare micro rhombohedra in tiny pockets
Colour: honey-yellow, wax-yellow, also yellowish to reddish-brown
Description: Reddingite is very commonly associated with fillowite, and in many cases it is not easy to distinguish the two minerals.
Reference: Brush and Dana (1878); American Mineralogist (1946): 31: 329-345; Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 720.; Rocks & Minerals (1995) 70:396-409
Fluorapatite
Formula: Ca5(PO4)3F
Localities: Reported from at least 86 localities in this region.
Fluorapatite var: Mn-bearing Fluorapatite
Formula: (Ca,Mn2+)5(PO4)3(F,Cl,OH) or Ca5([P,Mn5+]O4)3(F,Cl,OH)
Localities: Reported from at least 7 localities in this region.
Fluorapophyllite-(K)
Formula: KCa4(Si8O20)(F,OH) · 8H2O
Localities: Reported from at least 6 localities in this region.
Fluorite
Formula: CaF2
Localities: Reported from at least 43 localities in this region.
Fluorite var: Chlorophane
Formula: CaF2
Localities: Reported from at least 11 localities in this region.
Foitite
Formula: (□,Na)(Fe2+2Al)Al6(Si6O18)(BO3)3(OH)3OH
Forsterite
Formula: Mg2SiO4
Localities: Reported from at least 8 localities in this region.
Fourmarierite
Formula: Pb(UO2)4O3(OH)4 · 4H2O
Habit: pseudomorphs after uraninite
Colour: reddish
Description: "In a study at Harvard University, in 1964, both fourmarierite and vandendriesscheite were identified, by X-ray diffraction, as components of hard "gummite" pseudomorphs after uraninite from the Rock Landing quarry. Fourmarierite is reddish; vandendriesscheite, yellow. The material came from the Charles Thomas collection." Schooner (circa 1980s).
Reference: Schooner, Richard. (circa 1980s), Untitled manuscript on central Connecticut mineralogy.
Gahnite
Formula: ZnAl2O4
Localities: Reported from at least 9 localities in this region.
Galaxite ?
Formula: Mn2+Al2O4
Colour: dark green
Description: A dusting of a dark green mineral is seen in alleghanyite-kutnohorite specimens from the Jail Hill quarry. X-ray diffraction of a mixed sample shows faint peaks that correspond rather well to galaxite.
Reference: Schooner, Richard. (circa 1980s), Untitled manuscript on central Connecticut minerals.
Galena
Formula: PbS
Localities: Reported from at least 42 localities in this region.
Galena var: Argentiferous Galena
Formula: PbS
Description: Included in a list by Januzzi with no details, apparently based on early reports by Silliman of minerals actually from Lane's mine of Monroe. No modern data regarding the Ag content of galena from Connecticut has been published.
Reference: Januzzi, Ronald E. (1976): Mineral Localities of CT and Southeastern NY State. The Mineralogical Press, Danbury, Connecticut.
Galenobismutite ?
Formula: PbBi2S4
Reference: Januzzi, 1976. Mineral Localities of CT and Southeastern NY State
'Garnet Group'
Formula: X3Z2(SiO4)3
Localities: Reported from at least 63 localities in this region.
Gedrite
Formula: ☐{Mg2}{Mg3Al2}(Al2Si6O22)(OH)2
Gehlenite
Formula: Ca2Al(AlSiO7)
Habit: tetragonal prisms
Colour: light brown
Description: Tiny crystals in lens-like bodies of calc-silicate rock in the host Collins Hill Formation. Optical and X-ray study by Waldemar T. Schaller at the USGS indicate gehlenite, associated with diopside, grossular, wollastonite, and spurrite.
Reference: Schooner, Richard. (circa 1985), Untitled manuscript on central Connecticut mineralogy.
Gersdorffite
Formula: NiAsS
Habit: grains
Description: "An analysis by Fairchild, published in 1931, and quoted in the Seventh Edition of “Dana’s System of Mineralogy”, gave: iron 3.9, cobalt 0.7, nickel 31.6, antimony 9.1, arsenic 34.9, sulfur 17.1, and bismuth 0.4%" (Schooner 1958); with the ore minerals at Shepard's Lode (Gray 2005).
Reference: Schooner (1958); Gray (2005)
Gibbsite
Formula: Al(OH)3
Habit: radially fibrous masses, stalactitic and spherical concretions, and as incrustations
Reference: Januzzi, Ronald E. and David Seaman. (1976), Mineral Localities of Connecticut and Southeastern New York State and Pegmatite Minerals of the World. Taylor Assoc./Mineralogical Press, Danbury: 229.
'Gmelinite' ?
Description: This mineral is unknown from Connecticut trap rock. Likely confusion with chabazite variety phacolite.
Reference: Weber, Marcelle H. and Earle C. Sullivan. (1995): Connecticut Mineral Locality Index. Rocks & Minerals (Connecticut Issue): 70 (6): 403.
Gobbinsite
Formula: Na5(Si11Al5)O32 · 11H2O
Description: Asociated with foitite grading into elbaite, wodginite, cassiterite, and quartz.
Reference: Jarnot, Bruce M. (2011): Letters: Connecticut Update. Rocks & Minerals: 86(4): 299.
Goethite
Formula: α-Fe3+O(OH)
Localities: Reported from at least 63 localities in this region.
Gold
Formula: Au
Gonnardite
Formula: (Na,Ca)2(Si,Al)5O10 · 3H2O
Reference: Tschernich, R. (1992): Zeolites of the World, p.114
Goslarite ?
Formula: ZnSO4 · 7H2O
Graftonite ?
Formula: Fe2+Fe2+2(PO4)2
Description: Reported by Schooner (circa 1980s) as occurring in pieces from the Charles Thomas collection, along with triphylite, scorzalite, siderite, fairfieldite, augelite. Possible they could have come from the Palermo mine.
Reference: Schooner, Richard. (circa 1980s), Untitled manuscript on central Connecticut mineralogy.
Graphite
Formula: C
Localities: Reported from at least 26 localities in this region.
Grayite
Formula: (Th,Pb,Ca)(PO4) · H2O
Greenockite
Formula: CdS
Localities: Reported from at least 10 localities in this region.
Grossular
Formula: Ca3Al2(SiO4)3
Localities: Reported from at least 26 localities in this region.
Grossular var: Hessonite
Formula: Ca3Al2(SiO4)3
Habit: dodecahedral
Colour: orange to cinnamon
Description: Massive matrix material and lustrous crystals to 1.5 inches lining voids or hiding under calcite.
Reference: Murphy, Raymond H., Jr. (1966), Mineralogy of West Redding, Conn., Garnet Locality, Rocks and Minerals, 41(12): 896-897.
Groutite
Formula: Mn3+O(OH)
Grunerite
Formula: ☐{Fe2+2}{Fe2+5}(Si8O22)(OH)2
Description: siderite layers up to 1/2 inch were common in a vein of marcasite, cronstedtite, grunerite, and quartz (Schooner, circa 1985).
Reference: Schooner, Richard. (circa 1985), Untitled manuscript on central Connecticut mineralogy.
'Gummite'
Localities: Reported from at least 8 localities in this region.
Gypsum
Formula: CaSO4 · 2H2O
Localities: Reported from at least 26 localities in this region.
Gypsum var: Satin Spar Gypsum
Formula: CaSO4 · 2H2O
Reference: Van King
Gypsum var: Selenite
Formula: CaSO4 · 2H2O
'Halloysite'
Formula: Al2(Si2O5)(OH)4
Harmotome
Formula: (Ba0.5,Ca0.5,K,Na)5[Al5Si11O32] · 12H2O
Hastingsite
Formula: {Na}{Ca2}{Fe2+4Fe3+}(Al2Si6O22)(OH)2
Habit: subhedral prismatic
Colour: black
Reference: Schooner, Richard. (circa 1980s), Untitled manuscript on central Connecticut mineralogy.
Hedenbergite ?
Formula: CaFe2+Si2O6
Habit: radiating clusters
Colour: Greenish- Black
Reference: J. Zolan Collec.
Helvine
Formula: Be3Mn2+4(SiO4)3S
Habit: tetragonal, slightly cavernous showing trigonal indentations
Colour: honey-brown
Description: Two 0.8mm crystals found on a single specimen associated with the other common site minerals. Crystal faces are slightly pitted with sub-vitreous luster, dusted with a small amount of sugary white alteration. Could possibly be genthelvite.
Reference: Henderson, William A., Jr., Charles Weber and Marcelle Weber. (circa 1970), An Alpine Vein Deposit in Stratford, Conn. unpublished manuscript.; Henderson, William A., Jr., Charles Weber and Marcelle Weber. (circa 1970), Helvite from Stratford, Conn. unpublished manuscript.
Hematite
Formula: Fe2O3
Localities: Reported from at least 56 localities in this region.
Hematite var: Iron Rose
Formula: Fe2O3
Reference: P Cristofono collection
Hematite var: Specularite
Formula: Fe2O3
Description: In the baked arkose below the contact with the diabase.
Reference: Eaton, Frederick S. (1927): Mineral Localities of Connecticut. Rocks & Minerals, vol. 2, no. 4, pp. 141-2.; Longwell & Dana, 1932. Walks & Rides in Central CT & MA, p.228.
Hemimorphite
Formula: Zn4Si2O7(OH)2 · H2O
Herderite
Formula: CaBePO4(F,OH)
Description: undoubtedly hydroxylherderite as there is still but one or two chemically verified herderite specimen in the world and even the so-called type locality for true herderite does not have the species by modern chemical analyses. "Chemical analysis of herderite, collected by the author, at the State Forest Mine in East Hampton, Connecticut, indicate that it is the hydroxyl variety" (Januzzi 1994).
Reference: Januzzi (1994); Schooner (1958)
Heterosite
Formula: (Fe3+,Mn3+)PO4
Heulandite-Ca
Formula: (Ca,Na)5(Si27Al9)O72 · 26H2O
Localities: Reported from at least 10 localities in this region.
'Heulandite subgroup'
Localities: Reported from at least 30 localities in this region.
Hexahydrite ?
Formula: MgSO4 · 6H2O
Description: Discovered by Richard Schooner as an "efflorescence on schist" at an undisclosed Portland location, reported by Januzzi, but details lacking.
Reference: Januzzi, Ronald. (1976): Mineral Localities of CT and Southeastern NY State, p.234
'Hornblende'
Localities: Reported from at least 28 localities in this region.
Hübnerite ?
Formula: MnWO4
Description: Only confirmed ferberite pseudomorphs after scheelite have ever been found in the area, and only within the adjacent Old Mine Park. Analyses are needed to substantiate this mineral.
Reference: J. Zolan Collec.
Hureaulite
Formula: (Mn,Fe)5(PO4)2(HPO4)2 · 4H2O
Hydrokenoelsmoreite ?
Formula: 2W2O6(H2O)
Description: Reference includes a list of minerals reportedly found by Dick Schooner in a quartz vein in East Hampton, but with no supporting details. The mineral is listed as "ferritungstite".
Reference: Januzzi, 1976. Mineral Localities of CT and Southeastern NY State, p.234
Hydrokenoelsmoreite var: Ferritungstite ?
Reference: Reported by Dick Schooner (not analyzed?)
Hydrotungstite
Formula: WO3 · 2H2O
Description: Dehydrates to tungstite, whose presence outside of neighboring Old Mine Park has not been validated.
Reference: Jeremy Zolan
Hydroxylapatite
Formula: Ca5(PO4)3(OH)
Hydroxylherderite
Formula: CaBe(PO4)(OH,F)
Hydrozincite
Formula: Zn5(CO3)2(OH)6
'Hypersthene'
Formula: (Mg,Fe)SiO3
Ilmenite
Formula: Fe2+TiO3
Localities: Reported from at least 31 localities in this region.
Ilmenite var: Manaccanite
Formula: Fe2+TiO3
Reference: 5th and 6th Annual Reports of the Curators of the museum of Wesleyan University, Middletown, 1877.
Ilmenite var: Washingtonite
Formula: Fe2+TiO3
Reference: - Shepard, Charles U. (1842). On Washingtonite (a New Mineral), the Discovery of Euclase in Connecticut, and Additional Notices of the Supposed Phenakite of Goshen [MA], and Calstron-baryte of Schoharie, N. Y. (Am Journ. of Sci. 43:364).
'Indicolite'
Formula: A(D3)G6(T6O18)(BO3)3X3Z
Iron
Formula: Fe
Reference: Meteoritics, vol. 11, June 30, 1976, p. 111-130.; Scott, E.R.D. & Rajan, R.S. (1981) Metallic minerals, thermal histories and parent bodies of some xenolithic, ordinary chondrites. Geochimica et Cosmochimica Acta 45: 53-67.
Iron var: Kamacite
Formula: (Fe,Ni)
Reference: Meteoritics, vol. 11, June 30, 1976, p. 111-130.; Scott, E.R.D. & Rajan, R.S. (1981) Metallic minerals, thermal histories and parent bodies of some xenolithic, ordinary chondrites. Geochimica et Cosmochimica Acta 45: 53-67.
Ishikawaite
Formula: U4+Fe2+Nb2O8
Ixiolite
Formula: (Ta,Nb,Sn,Fe,Mn)4O8
Ixiolite var: Wolframoixiolite
Formula: (Nb,W,Ta,Fe,Mn,Nb)2O4
Habit: acicular
Colour: black
Description: Elongated, thin crystals in albite/quartz/annite matrix, with unknown translucent, orange-red coating.
Reference: Former Richard Schooner collection
Jacobsite
Formula: Mn2+Fe3+2O4
Description: "Specimens of tephroite from the Jail Hill quarry contain magnetic grains, shown (by X-ray and microprobe study at the University of Michigan) to be jacobsite. The material ranges from ferroan jacobsite to manganoan magnetite, within individual grains. A few specimens show it rather abundantly." Specimens are in the Harvard Mineralogical Museum.
Reference: Schooner, Richard. (circa 1980s), Untitled manuscript on central Connecticut minerals.
Jarosite
Formula: KFe3+ 3(SO4)2(OH)6
Johannite
Formula: Cu(UO2)2(SO4)2(OH)2 · 8H2O
J