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Slocum Prospect, East Hampton (Chatham), Middlesex Co., Connecticut, USA
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Latitude: 41°31'56"N
Longitude: 72°28'16"W
 
 
Several excavations surrounding a pegmatite that was operated as a fee collecting site by Robert Gallant in the 1960s, though it was closed in the late 1970s (Albini, 1979). The most complete description is given by Cameron et al (1954):

The property is owned by Edwin Slater, R. F. D., East Hampton. According to local reports, feldspar mining was begun about 1890 by John White. F. A. Slocum later purchased the property and mined feldspar between 1920 and 1922. The prospect was mapped by E. N. Cameron and V. E. Shainin in August 1943…. It is a partly backfilled opencut 90 feet long, 20 feet wide, and 2 to 15 feet deep.

The pegmatite is a lenticular body at least 80 feet long. It ranges from 1 to about 10 feet in thickness and has an average thickness of 8 feet. It strikes N. 70° E. and dips 18°-60° N. In the cliff east of the quarry the pegmatite ends down dip 25 feet from its exposure in the working. Its keel plunges S. 82° W. at a gentle angle. East of the quarry the pegmatite has been completely removed by erosion, but it may extend westward beneath glacial till. East of the cut the beryl-bearing pegmatite truncates an older, barren, pegmatite. The latter consists of quartz, plagioclase, [microcline] perthite, and minor muscovite. The beryl-bearing pegmatite is discordant to thin-bedded mica quartzites whose bedding and foliation strike slightly north of east and dip gently westward.

The pegmatite is distinctly zoned. The border zone is ¼ to 12 inches thick and consists of fine-grained quartz, plagioclase and [microcline] perthite, with accessory garnet, tourmaline, and beryl.

The wall zone, 1.2 to 1.6 feet thick, consists of quartz, [microcline] perthite, and plagioclase, with accessory beryl, black tourmaline, scrap muscovite, and rare biotite and columbite-tantalite. The zone becomes progressively coarser-grained toward the center of the pegmatite. Its inner part is nearly free of beryl.

The outer intermediate zone, 1 to 6 feet thick, consists of coarse-grained white to cream-colored [microcline] perthite and granular quartz. The zone is exposed only at the eastern end of the core where it is an indistinct hood-shaped body between the wall zone and the core.

The core-margin zone, 6 inches to 1 foot thick, consists of granular milky quartz, coarse-grained [microcline] perthite, and subordinate beryl. Quartz and [microcline] perthite are about equal in abundance…

The core is probably 5 to 7 feet thick but only its upper margin is visible. It consists of granular milky quartz and a few scattered [microcline] perthite crystals.

Beryl occurs in the pegmatite in yellow (“golden”), green, and blue euhedral crystals. In the border zone they range in size from 1/32 to 1/34 inch in diameter and from 1/2 inch to 2 1/2 inches long. Crystals as much as 8 inches in length and 1 inch in diameter occur in the core-margin zone.


There is also a smaller pegmatite exposed in a trench near the top of the hill that produced small but very clear garnet and heliodor.

Regarding beryl, Schooner (1958) reports that:

A few years ago, Frank Bibik reopened the Slocum Quarry and worked it sporadically for specimens and gems of golden and greenish beryl. Some superb crystals were obtained at that time. The author has seen one marvelously etched crystal, of a rich greenish-golden color and almost flawless, in the collection of Robert Gallant. It was embedded in clay in a small cavity. The operator also unearthed one of these truly gorgeous crystals.


and:

Magnificent heliodor crystals, completely flawless and beautifully formed, are on display in the Harvard University Museum [http://www.mindat.org/photo-427820.html]. They were collected at the Slocum Quarry in East Hampton by the late Louis W. Little, many years ago. The author used to see these crystals quite often, while the Little collection was still in the area. As he remembers them, some are two or three inches in length and almost an inch in diameter. They have a pure golden-color, with no tint of green.


Schooner (1961) provides an update:

The Slocum quarry, which has been intermittently active in the past few years, has produced many crystals of golden beryl, sharp in form and of the finest gem quality. Indeed, this is one of the principal heliodor sources in North America....Of late, several magnificent specimens of a different type have been recovered. Those are deeply etched, frosty-looking, greenish-golden gem crystals, from cavities along a fault (?) which runs through the lower end of the quarry. The Gallant collection includes a superb crystal, with rounded diamond-shaped etch-pits on virtually every surface. It is over two inches long.


Most beryls frozen in matrix tend to be very elongated and were segmented along basal cleavages before the matrix was fully frozen. Rarely is a complete beryl intact upon removal and the segments are usually capped by "healed" cleavages rather than true pinacoidal faces. True terminations show complete or partial pyramidal forms.

Mineral List

Actinolite ?
Albite
var: Cleavelandite
Annite
Autunite
Bavenite
Bertrandite
Beryl
var: Aquamarine
var: Heliodor
Columbite-(Fe)
Diopside ?
Fluorapatite
Fluorite
'Garnet'
Grossular ?
Ixiolite
var: Wolframoixiolite

Kaolinite
Melanterite ?
Microcline
Microlite Group
var: Uranmicrolite (of Hogarth 1977)
'Monazite'
Muscovite
Opal
var: Opal-AN

Pyrite
Pyrochlore Group ?
Pyrrhotite ?
Quartz
Rutile
var: Strüverite

Samarskite-(Y) ?
'Scapolite'
Scheelite
Schorl
Spessartine ?
'Tantalite' ?
Tanteuxenite-(Y)
Titanite
Tremolite ?
Uraninite
Uranophane ?
'Xenotime' ?
Zircon
var: Cyrtolite



43 entries listed. 30 valid minerals.

The above list contains all mineral locality references listed on mindat.org. 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 mindat.org 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.

References

Montague, S. A. (1937): Some Mineral Localities Near Portland, Conn. Rocks & Minerals: 12(5): 145.

Cameron, Eugene N., David M. Larrabee, Andrew H. McNair, James T. Page, Glenn W. Stewart, and Vincent E. Shainin. (1954): Pegmatite Investigations 1942-45 New England; U. S. Geological Survey Professional Paper 255.

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.

Jones, Robert W. (1960): Luminescent Minerals of Connecticut, A Guide to Their Properties and Locations. Fluorescent House, Branford, Connecticut.

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

Ryerson, Kathleen. (1972): Rock Hound's Guide to Connecticut. Pequot Press.

Henderson, William A., Jr. (1975): The Bertrandites of Connecticut. The Mineralogical Record: 6(3): 114-123.

Januzzi, Ronald. (1976): Mineral Localities of Connecticut and Southeastern New York State. (Taylor Assoc./Mineralogical Press).

Albini, Anthony J. (1979): Selected Pegmatite Quarries of The Central Connecticut Region. Central Connecticut State University Masters thesis.

Jarnot, Bruce. (1989): Minerals New to the Portland Area Pegmatites of Central Connecticut. Abstract from the 16th Rochester Mineralogical Symposium April 7, 1989, in Rocks & Minerals: 64(12): 471.

Weber, Marcelle H. and Earle C. Sullivan. (1995): Connecticut Mineral Locality Index. Rocks & Minerals (Connecticut Issue): 70(6): 403.

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