The Clark Hill Quarries are located in the Meshomasic State Forest off of Woodcutter's Road. Look for the State Forest Entrance sign on Clark Hill Road, East Hampton. Collecting is allowed by STATE PERMIT ONLY (rules) (see News page for permitted club collecting dates!).
Based on my experience, these quarries (State Forest Quarry #1 and the Nathan Hall Quarry) are quite productive! They have produced two of my best self-collected pieces and many other fine examples of simple pegmatite minerals. In particular, sharp muscovite crystals are very common at the Hall Quarry and the large, dark spessartine garnets from there, although fairly rare, are awesome. Biotite is also common, mostly in bladed crystals up to several feet long. Beryl is uncommon, but crystals can be large, gemmy, and terminated and vary in color from yellow through green to aqua. Zircon, uranium minerals (beautiful autunite and torbernite halos around altered uraninite), and fluorapatite are sprinkled throughout. Albite is abundant; sheaf-like crystal aggregates with muscovite are found on pocket wall fragments at SFQ#1. Microcline occurs as small pocket crystals (SFQ#1) or in very large matrix crystals. Unfortunately much schorl tourmaline has altered to muscovite, but there are interesting tapered pseudomorphs similar to those from Wentworth, NH. Massive quartz, which encloses the sharp micas and matrix microclines, is very abundant at Hall, but good crystals are usually pocket micros. Although tiny columbites are common, large ones are very rare and when you find one, you will remember every part of the experience! These quarries are full of surprises for the persistent collector. More recently, another pegmatite near the intersection of Woodchopper's Road and the logging road that leads to the quarries was uncovered by logging activity and the core zone has been prospected, yielding many beryls and some good garnets and columbites.
Based on the few references, the Hall Quarry appears to have operated completely before 1922 (see below). There is nothing specific in the mineralogical literature, but presumably it was quarried for feldspar and/or mica. The F. W. Beers County Atlas of Middlesex, Connecticut, published in 1874, shows a large rectangle of land north of Clark Hill Road owned by "N. Hall". The Hall Cemetery is on Clark Hill Road near the entrance to Woodchopper's Road. I have found remnants of an old, late 19th century chewing tobacco hip pocket can, but also more recent artifacts like a corroded Gablinger's beer can (the first lite beer!) and a Cott soda bottle.
SFQ#1 was quarried for mica and feldspar for only a few months in 1942 and 1943. Presumably the low muscovite mica content (see below) and high biotite mica content in the graphic granite, which is abundant in the dumps and is typically shipped for ceramics, make this deposit uneconomic. Even a small amount of iron-rich minerals in the feldspar results in brown staining of the ceramic glaze.
Note: These quarries should not be confused with State Forest Quarry #2, which is located along Mine Brook SW of the cobalt mines. SFQ#2 is the locality for many rare phosphate minerals similar to those found at the Palermo Mine in North Groton, NH.
Here's what's in the scant mineralogical literature concerning these sites:
W. G. Foye, of Wesleyan University wrote in 1922 (MINERAL LOCALITIES IN THE VICINITY OF MIDDLETOWN, CONNECTICUT. American Mineralogist, Volume 7, pages 4-12): "Another quarry long inactive is the Nathan Hall quarry. It is still noted for the abundance of the rose quartz to be obtained from its dumps. No other quarry compares with it in its yield of this mineral." {Not sure what he's on about as I've never seen any there! But there is plenty of red-stained quartz. However, one small piece of rose quartz was found by a club member in the logging road near the quarry.}
Cameron
et. al. in PEGMATITE INVESTIGATIONS 1942-45 NEW ENGLAND (USGS Prof. Paper 255,
1954) provides the best description and history of the STATE
FOREST NO. 1 QUARRY.
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. From East Hampton travel northward along the western shore of Lake Pocotopaug for 1.5 miles to an asphalt road leading westward. Follow this road for about 1.5 miles, then turn northward on a gravel road that leads about 1/2 mile to the quarry.
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 perthite and of quartz and 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 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.
Dick Schooner wrote in his 1958 tome THE MINERALOGY OF THE PORTLAND-EAST HAMPTON-MIDDLETOWN-HADDAM AREA IN CONNECTICUT:
Beryl: "beautiful crystals are still to be found at the State Forest Quarry No. 1"
Columbite: occurs at "one of the quarries in Meshomasic State Forest far to the northwest of Lake Pocotopaug, where Ralph Lieser obtained a broken crystal which measured two or three inches across."
Spessartine: "Rather large crystals, up to four inches in diameter, have been collected at the State Forest Quarry No. 1"
Torbernite: reports its presence at SFQ#1
Uraninite: "Traces are seen at the State Forest Quarry No. 1"
In 1960, Robert W. Jones, Jr. reported in LUMINESCENT MINERALS OF CONNECTICUT, the following luminescent minerals at State Forest Quarry No. 1: Albite, Quartz, Scheelite.
In his 1961 work on the whole state (THE MINERALOGY OF CONNECTICUT), Dick Schooner also reports:
Beryl: "The Hall Quarry, in Meshomasic State Forest, on Clark Hill, is a locality for green and yellow crystals, but not gemmy ones."
Spessartine: "Black-stained dark reddish-orange crystals, three or four inches through, and well formed, have come from the Hall Quarry"
In 1972, Kathleen Ryerson (ROCK HOUND'S GUIDE TO CONNECTICUT) also reported that albite, quartz, and scheelite occur at SFQ#1. I have to question the scheelite. As Cameron above mentions, SFQ#1 was worked for a short time by the Worth Spar Co., which had another quarry farther south on Hog Hill near Middle Haddam. I have a scheelite well documented from this more southerly quarry that was collected by Dick Schooner and formerly belonged to P. Zodac of Rocks & Minerals magazine, and dealer Larry Conklin. Therefore, I think Ryerson is confusing the two localities as no one else mentions scheelite on Clark Hill.