State Forest Quarry No. 1 (State Forest #1 Quarry; Clark Hill Quarry), East Hampton (Chatham), Middlesex Co., Connecticut, USA
|Latitude & Longitude (WGS84):||41° 35' 43'' North , 72° 32' 28'' West|
|Latitude & Longitude (decimal):||41.59528,-72.54111|
|Köppen climate type:||Dfa : Hot-summer humid continental climate|
The main details about this granite pegmatite quarry are given by Cameron et al (1954):
The State Forest No. 1 quarry lies in the town of East Hampton, 2.3 miles N. 55° W. of the center of East Hampton village...
The property is owned by the State of Connecticut and is administered by the Forestry Department, State Office Building, Hartford. The New Haven Trap Rock Co., 67 Church Street, New Haven, quarried the pegmatite in October and November 1942, and the Worth Spar Co., Inc., Cobalt, operated the deposit for 3 months in the summer of 1943. The workings consist of an opencut about 90 feet long, 40 feet wide and 15 feet deep. E. N. Cameron examined the property in November 1942.
At the time of examination, the pegmatite was so poorly exposed that its form, attitude and extent could not be determined. Probably it strikes north-northeast. At the entrance to the quarry, and on the east side of the cut, pegmatite is exposed in irregular crosscutting contact with quartz-mica schists. However, it is not certain whether the schists are the true walls of the pegmatite or merely inclusions in it.
The pegmatite is composed chiefly of coarse-grained quartz and plagioclase, intergrown in various proportions. Muscovite, garnet, tourmaline, and beryl are also present. Pods of [microcline] perthite and of quartz and [microcline] perthite as much as 4 feet long and 2 feet wide are irregularly distributed through the pegmatite.
Mica books 2 to 15 inches in diameter and 3/4 to 4 inches thick are present in the pegmatite. At the time of examination, however, the quarry walls were obscured to such an extent that the distribution of the mica could not be determined satisfactorily. According to the quarrymen, most of the mica mined in 1942 was associated with a pod of coarse-grained quartz and [microcline] perthite.
The mica is a clear, light rum, moderately hard, free-splitting muscovite. Most books are free of inclusions, but some contain garnet and plagioclase crystals. All the books are more or less marred by “A” structure, ruling, and cross-fracturing, and many books are wedge-shaped. Beryl occurs as crystals 1 to 8 inches in length and 1/2 to 5 inches in diameter.
Mica was found associated with one or more pods, and scattered books of mica occur elsewhere in the pegmatite. The average percentage of crude mica recovered from rock mined was very low, however. Neither of the attempts made to mine the deposit in 1942 and 1943 was successful. (Cameron)
Scheelite is reported in the literature as occurring here, but the report almost certainly results from confusion with the Worth Quarry that was also operated by the Worth Spar Co. on Hog Hill near Middle Haddam where scheelite was found.
Collecting is allowed via permit issued by the Connecticut DEEP to educational organizations (schools, mineral clubs, etc.). See link below.
14 valid minerals.
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
358.9 - 419.2 Ma
Age: Devonian (358.9 - 419.2 Ma)
Stratigraphic Name: Littleton Formation
Description: Gray to silvery, generally non-rusty, medium-grained, massive to well-layered alternating schist and micaceous quartzite, composed of quartz, muscovite, biotite, garnet, and oligoclase, also staurolite, graphite, and ilmenite, and in certain areas kyanite or sillimanite in schist.
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.