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Cheshire Traprock Quarry, Cheshire, New Haven Co., Connecticut, USAi
Regional Level Types
Cheshire Traprock QuarryQuarry
Cheshire- not defined -
New Haven Co.County

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Lock Map
Latitude & Longitude (WGS84):
41° 30' 59'' North , 72° 55' 28'' West
Latitude & Longitude (decimal):
Locality type:
Nearest Settlements:
Cheshire Village5,786 (2017)2.6km
Cheshire29,443 (2017)2.8km
Prospect9,476 (2017)4.8km
Meriden59,988 (2017)10.1km
Wallingford17,712 (2017)10.7km

An old, long inactive traprock quarry in Peck Mountain on the West Rock diabase sill. Exact dates of activity are uncertain, but the quarry is not mentioned in literature older than Schairer (1931). It is active, though relatively small, on 1934 aerial photographs, the first available. Hiller (1971) calls it inactive.

Schooner (1961) calls this area "near Roaring Brook" or just "Roaring Brook", though the well-known waterfall exposure is 2.4 miles south of the quarry. He references Dana's System of Mineralogy 5th edition (1875), which correctly says Roaring Brook is 14 miles north of New Haven (the quarry is about 16.5). It is unlikely the quarry is that old and because Roaring Brook cuts a gorge through the sill, the falls on the brook is a separate locality.

The most productive area for minerals after quarrying was over is at the northwest end. Analcime and natrolite, typically together (with mostly calcite, prehnite and micro-albite crystals), were common there, but are very rare at other traprock quarries in Connecticut.

Some Cheshire specimens have been attributed to the traprock quarries in Woodbury and Southbury, Connecticut but natrolite and analcime are very rare there and the extrusive basalt matrix is very fine-grained or aphanitic. The West Rock sill diabase matrix, being intrusive, is relatively coarse-grained (1-2mm) and the dark augite and light plagioclase grains give it a salt and pepper appearance quite different from the Woodbury/Southbury matrix. Many Cheshire specimens also have a brown stain on the minerals that is unlike the other quarries. This is "limonite" that is easily cleaned off if desired.

Regions containing this locality

North America PlateTectonic Plate

Select Mineral List Type

Standard Detailed Strunz Dana Chemical Elements

Commodity List

This is a list of exploitable or exploited mineral commodities recorded at this locality.

Mineral List

12 valid minerals.

Detailed Mineral List:

Formula: Na(AlSi3O8)
Habit: tabular micros twinned once down the center
Colour: colorless to white
Description: Very unusual for traprock, the micro crystals form a druse lining some voids and are clear and tabular with a single twin plane down the center, parallel to the tabular habit.
Reference: Weber, Marcelle H. and Earle C. Sullivan. (1995), Connecticut Mineral Locality Index. Rocks & Minerals (Connecticut Issue): 70(6): 403.
Formula: Na(AlSi2O6) · H2O
Habit: trapezohedra
Colour: white
Description: good though generally small (~1 cm or less) crystals associated with prehnite, natrolite, micro heulandite
Reference: Tschernich, R. (1992): Zeolites of the World, p.65, 114; Rocks & Minerals (1995) 70:396-409
Habit: rectangular prisms with square cross-section and pinacoidal terminations
Colour: chalky white
Description: "Crystalline seams of apophyllite from the Cheshire trap rock quarry were identified by the greenish-white fluorescence of melted portions, under UV." Januzzi (1976). As corroded, chalky white, rectangular prism microcrystals with pinacoid terminations.
Reference: Januzzi, Ronald. (1959): The Minerals of Western Connecticut and Southeastern New York State. Taylor Assoc./Mineralogical Press, Danbury.; Januzzi, Ronald. (1976): Mineral Localities of Connecticut and Southeastern New York State. Taylor Assoc./Mineralogical Press, Danbury.; Harold Moritz collection.
Formula: CaCO3
Reference: Tschernich, R. (1992): Zeolites of the World, p.65
Formula: (Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
Habit: cyclicly-twinned rhombohedra
Colour: colorless
Description: As glassy, colorless, cyclicly-twinned microcrystals.
Reference: Harold Moritz collection; Tschernich, Rudy. (1992), Zeolites of the World. Geoscience Press, Phoenix: 65, 114.
Formula: CuFeS2
Habit: tetrahedral
Colour: tarnished blue, bronze, magenta
Description: micro crystals with heulandite
Reference: Januzzi (1959); Alfred Patrie collection
'Chlorite Group' ?
Description: Listed by Januzzi (1976) without details. Either an alteration product or confusion with pumpellyite.
Reference: Tschernich, R. (1992): Zeolites of the World, p.114
Formula: CaB(SiO4)(OH)
Colour: white, pale green
Description: "white ball-shaped crystals" Hiller (1971); road widening just south of the quarry in the late 1990s turned up some of the more typical glassy, pale green crystals.
Reference: Tschernich, R. (1992): Zeolites of the World, p.65, 114; Rocks & Minerals (1995) 70:396-409
Epidote ?
Formula: {Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
Description: Reference provides no details.
Reference: Rocks & Minerals (1995) 70:396-409
Formula: CaSO4 · 2H2O
Description: "Found as occurring in amygdaloidal cavities" Januzzi (1959)
Reference: Januzzi (1959); Januzzi (1976)
'Heulandite subgroup'
Habit: coffin-shaped
Colour: brown
Description: As microcrystals in the usual coffin shape, translucent with numerous inclusions.
Reference: Harold Moritz collection
Formula: CaAl2Si4O12 · 4H2O
Reference: Kevin Czaja Collection, Ex: Marcelle Weber Coll: m2677. 9-9-63
Formula: Na2Al2Si3O10 · 2H2O
Habit: acicular prisms with tetragonal pyramidal terminations
Colour: white
Description: single and bundles of crystals to 1 inch or so, associated with analcime, prehnite, micro heulandite
Reference: Tschernich, R. (1992): Zeolites of the World, p.65; Rocks & Minerals (1995) 70:396-409
Formula: Ca2Al2Si3O10(OH)2
Habit: spherical aggregates
Colour: pale green to blue-green
Description: spherical aggregates with analcime, natrolite and micro heulandite
Reference: Tschernich, R. (1992): Zeolites of the World, p.65, 114; Rocks & Minerals (1995) 70:396-409
Description: common in local traprock as micro aggregates and druses.
Reference: Rocks & Minerals (1995) 70:396-409
Formula: SiO2
Description: Reference provides no details, but plausible based on other traprock localities.
Reference: Ryerson, Kathleen, H: Rock Hounds Guide to Connecticut 1972
Quartz var: Agate
Habit: microcrystalline
Description: Lining cavities.
Reference: Januzzi (1959); Januzzi (1976)
Quartz var: Chalcedony
Formula: SiO2
Habit: microcrystalline
Description: Lining cavities.
Reference: Januzzi (1959); Januzzi (1976)

List of minerals arranged by Strunz 10th Edition classification

Group 2 - Sulphides and Sulfosalts
Group 4 - Oxides and Hydroxides
var: Agate4.DA.05SiO2
var: Chalcedony4.DA.05SiO2
Group 5 - Nitrates and Carbonates
Group 7 - Sulphates, Chromates, Molybdates and Tungstates
Gypsum7.CD.40CaSO4 · 2H2O
Group 9 - Silicates
Analcime9.GB.05Na(AlSi2O6) · H2O
Chabazite-Ca9.GD.10(Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
Epidote ?9.BG.05a{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
Laumontite9.GB.10CaAl2Si4O12 · 4H2O
Natrolite9.GA.05Na2Al2Si3O10 · 2H2O
Unclassified Minerals, Rocks, etc.
'Chlorite Group' ?-
'Heulandite subgroup'-

List of minerals arranged by Dana 8th Edition classification

Group 2 - SULFIDES
AmBnXp, with (m+n):p = 1:1
Gypsum29.6.3.1CaSO4 · 2H2O
Group 54 - NESOSILICATES Borosilicates and Some Beryllosilicates
Borosilicates and Some Beryllosilicates with B in [4] coordination
Group 58 - SOROSILICATES Insular, Mixed, Single, and Larger Tetrahedral Groups
Insular, Mixed, Single, and Larger Tetrahedral Groups with cations in [6] and higher coordination; single and double groups (n = 1, 2)
Epidote ?58.2.1a.7{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
Group 72 - PHYLLOSILICATES Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings
Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings with 4-membered rings
Group 75 - TECTOSILICATES Si Tetrahedral Frameworks
Si Tetrahedral Frameworks - SiO2 with [4] coordinated Si
Group 76 - TECTOSILICATES Al-Si Framework
Al-Si Framework with Al-Si frameworks
Group 77 - TECTOSILICATES Zeolites
Zeolite group - True zeolites
Analcime77.1.1.1Na(AlSi2O6) · H2O
Chabazite-Ca77.1.2.1(Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
Laumontite77.1.1.4CaAl2Si4O12 · 4H2O
Natrolite77.1.5.1Na2Al2Si3O10 · 2H2O
Unclassified Minerals, Mixtures, etc.
'Chlorite Group' ?-
'Heulandite subgroup'-
var: Agate
var: Chalcedony-SiO2

List of minerals for each chemical element

H AnalcimeNa(AlSi2O6) · H2O
H NatroliteNa2Al2Si3O10 · 2H2O
H PrehniteCa2Al2Si3O10(OH)2
H DatoliteCaB(SiO4)(OH)
H GypsumCaSO4 · 2H2O
H Chabazite-Ca(Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
H LaumontiteCaAl2Si4O12 · 4H2O
H Epidote{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
B DatoliteCaB(SiO4)(OH)
C CalciteCaCO3
O AnalcimeNa(AlSi2O6) · H2O
O NatroliteNa2Al2Si3O10 · 2H2O
O PrehniteCa2Al2Si3O10(OH)2
O DatoliteCaB(SiO4)(OH)
O CalciteCaCO3
O AlbiteNa(AlSi3O8)
O QuartzSiO2
O GypsumCaSO4 · 2H2O
O Chabazite-Ca(Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
O LaumontiteCaAl2Si4O12 · 4H2O
O Quartz (var: Chalcedony)SiO2
O Epidote{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
Na AnalcimeNa(AlSi2O6) · H2O
Na NatroliteNa2Al2Si3O10 · 2H2O
Na AlbiteNa(AlSi3O8)
Na Chabazite-Ca(Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
Al AnalcimeNa(AlSi2O6) · H2O
Al NatroliteNa2Al2Si3O10 · 2H2O
Al PrehniteCa2Al2Si3O10(OH)2
Al AlbiteNa(AlSi3O8)
Al Chabazite-Ca(Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
Al LaumontiteCaAl2Si4O12 · 4H2O
Al Epidote{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
Si AnalcimeNa(AlSi2O6) · H2O
Si NatroliteNa2Al2Si3O10 · 2H2O
Si PrehniteCa2Al2Si3O10(OH)2
Si DatoliteCaB(SiO4)(OH)
Si AlbiteNa(AlSi3O8)
Si QuartzSiO2
Si Chabazite-Ca(Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
Si LaumontiteCaAl2Si4O12 · 4H2O
Si Quartz (var: Chalcedony)SiO2
Si Epidote{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
S ChalcopyriteCuFeS2
S GypsumCaSO4 · 2H2O
K Chabazite-Ca(Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
Ca PrehniteCa2Al2Si3O10(OH)2
Ca DatoliteCaB(SiO4)(OH)
Ca CalciteCaCO3
Ca GypsumCaSO4 · 2H2O
Ca Chabazite-Ca(Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O
Ca LaumontiteCaAl2Si4O12 · 4H2O
Ca Epidote{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
Fe ChalcopyriteCuFeS2
Fe Epidote{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
Cu ChalcopyriteCuFeS2

Regional Geology

This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.

Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org

Early Jurassic
174.1 - 201.3 Ma

ID: 2952610
West Rock Dolerite

Age: Early Jurassic (174.1 - 201.3 Ma)

Stratigraphic Name: West Rock Dolerite

Description: Dark-gray to greenish-gray (weathers bright orange to brown), medium- to fine-grained, grading from basalt near contacts to fine-grained gabbro in the interior, generally massive with well-developed columnar jointing, composed of plagioclase and pyroxene with accessory opaques and locally devitrified glass, quartz, or olivine.

Comments: Part of Central Lowlands; Newark Terrane - Hartford and Pomperaug Mesozoic Basins Original map source: Connecticut Geological and Natural History Survey, DEP, in cooperation with the U.S. Geological Survey, 2000, Bedrock Geology of Connecticut, shapefile, scale 1:50,000

Lithology: Major:{gabbro}

Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. [133]

201.3 - 251.902 Ma

ID: 3188891
Mesozoic volcanic and intrusive rocks

Age: Triassic (201.3 - 251.902 Ma)

Comments: Connecticut Valley Basin

Lithology: Mafic volcanic rocks; conglomerate,arkose,shale,arenite

Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. [154]

Data and map coding provided by Macrostrat.org, used under Creative Commons Attribution 4.0 License


Sort by

Year (asc) Year (desc) Author (A-Z) Author (Z-A)
Schairer, J. F. (1931), The Minerals of Connecticut. State Geological and Natural History Survey Bulletin 51, Hartford, Conn.
Januzzi, Ronald. (1959), The Minerals of Western Connecticut and Southeastern New York State. Taylor Assoc./Mineralogical Press, Danbury.
Schooner, Richard. (1961), The Mineralogy of Connecticut. Fluorescent House, Branford, Connecticut.
Hiller, John, Jr. (1971), Connecticut Mines and Minerals. Privately published.
Ryerson, Kathleen. (1972), Rock Hound's Guide to Connecticut. Chester, Conn.: Pequot Press.
Januzzi, Ronald. (1976), Mineral Localities of Connecticut and Southeastern New York State. Taylor Assoc./Mineralogical Press, Danbury.
Brunet, William M. (1980), Minerals of the Trap Rock Ridges of the Connecticut Valley With Emphasis on Reed’s Gap Quarry Near Durham. Rocks and Minerals: 55 (6).
Tschernich, Rudy. (1992), Zeolites of the World. Geoscience Press, Phoenix: 65, 114.
Weber, Marcelle H. and Earle C. Sullivan. (1995), Connecticut Mineral Locality Index. Rocks & Minerals (Connecticut Issue): 70 (6): 403.

Mindat Articles

Mineralogy of the Cheshire Traprock Quarry by Rowan Lytle

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