Help|Log In|Register|
Home PageMindat NewsThe Mindat ManualHistory of MindatCopyright StatusManagement TeamContact UsAdvertise on Mindat
Donate to MindatSponsor a PageSponsored PagesTop Available PagesMindat AdvertisersAdvertise on MindatThe Mindat Store
Minerals by PropertiesMinerals by ChemistryRandom MineralSearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
StatisticsThe ElementsMember ListBooks & MagazinesMineral Shows & EventsThe Mindat DirectoryHow to Link to MindatDevice Settings
Photo SearchPhoto GalleriesNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day Gallery

Great Hill Pond Brook pegmatite, Cobalt, East Hampton (Chatham), Middlesex Co., Connecticut, USA

This page is currently not sponsored. Click here to sponsor this page.
Latitude & Longitude (WGS84): 41° 15'' South , 72° 34'' West
Latitude & Longitude (decimal): 41.5708333333, -72.5594444444

A granite pegmatite exposed at the waterfall on Great Hill Pond Brook about 350 meters downstream of the pond. Prospected before 1927 based on its first mention in the literature by Rice and Foye (1927):

The path which we follow up the valley is in places indistinct, and, when the brook is full, as is usual in the springtime, requires some wading. At the head of the valley, we find that the brook comes down in a cascade over a ledge of pegmatite. Our path has followed mostly the right bank of the brook (our left, as we face upstream). The ledge of pegmatite extends some distance to our right from the situation of the cascade. We see at once that considerable work has been done in quarrying pegmatite. The quarry, however, was soon abandoned. Very likely one reason for its abandonment was that the pegmatite there contains large quantities of black tourmaline and black mica; since the presence of dark, iron-holding minerals in large quantity diminishes the value of the rock for the purposes to which it is applied. We cross the brook (an easy task in late summer, but in spring and early summer it requires some wading), and ascend by a road or path a short distance to the right of the exposure of pegmatite. The large masses of black tourmaline are very conspicuous, and other somewhat interesting minerals may be seen. Near the top of the exposure of pegmatite, we find a path leading east, passing a couple of shanties which were used while the quarry was being worked and one of which is badly ruined.

Schooner (1958 and/or 1961) mentions well-formed black tourmaline and "spessartine" (likely almnadine-spessartine mix) from here. In 1961 he describes similar garnet from the Nathan Hall quarry on Clark Hill a mile or so to the NE Schooner later incorrectly calls the Nathan Hall Quarry the "Hale Quarry" in his unpublished central Connecticut mineralogy. This occurs in the text for "spessartine" localities right after he mentions garnet from the Great Hill Pond Brook falls pegmatite. This may have led to confusion by Hiller (1971) who marks this prospect on a map of the Cobalt area localities as "Nathan Hale [sic] Quarry". While it may just be an error by Hiller (the source he used for the name is not recorded), it is possible that Nathan Hall, who's family owned much land in the area in the 19th century, prospected this pegmatite as well, given that Foye in 1922 stated that the Nathan Hall Quarry was long abandoned. Nathan Hall had quarry properties in Haddam Neck also. However, so far the exact history of this little prospect is unknown.

The brook is the border between Portland (west) and the Cobalt section of East Hampton (east), but because the pegmatite extends mostly east of the brook, it is listed here as in the latter town. The site is now residential private property.

Mineral List

5 valid minerals.

The above list contains all mineral locality references listed on This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.


Rice, William North and Wilbur Garland Foye. (1927), Guide to the Geology of Middletown, Connecticut, and Vicinity. State Geological and Natural History Survey Bulletin 41.

Schooner, Richard. (1958), The Mineralogy of the Portland-East Hampton-Middletown-Haddam Area in Connecticut (With a few notes on Glastonbury and Marlborough). Published by Richard Schooner; Ralph Lieser of Pappy’s Beryl Shop, East Hampton; and Howard Pate of Fluorescent House, Branford, Connecticut.

Stugard, Frederick, Jr. (1958), Pegmatites of the Middletown Area, Connecticut. USGS Bulletin 1042-Q.

Jones, Robert W. (1960), Luminescent Minerals of Connecticut, a Guide to Their Properties and Locations.

Schooner, Richard. (1961), The Mineralogy of Connecticut. Fluorescent House, Branford, Connecticut.

Hiller, John, Jr. (1971), Connecticut Mines and Minerals. Privately published: 52.

Schooner, Richard. (circa 1980s), Untitled manuscript on central Connecticut mineralogy.

Mineral and/or Locality is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © and the Hudson Institute of Mineralogy 1993-2017, except where stated. relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: April 25, 2017 09:40:55 Page generated: October 16, 2016 15:28:27
Go to top of page