Long Hill prospects (Turkey Hill prospects), Haddam, Middlesex County, Connecticut, USAi

Regional Level Types
Long Hill prospects (Turkey Hill prospects)	Group of Prospects
Haddam	- not defined -
Middlesex County	County
Connecticut	State
USA	Country

I have just procured two of the finest crystals I ever had in my possession. One of them is a perfect hexagonal prism, about two inches long, and an inch and a half in diameter. The faces forming its terminations are at right angles with the sides, and wear as fine a polish as the hand of Nature can produce. The color is a brilliant emerald green, and, indeed, the crystal appears to possess more of the characters of the emerald, than of the beryl.

The Long Hill prospects are located in Haddam about 12 miles S 20° E from the center of town (fig. 31). They are on 160 acres owned by Mrs. Sona Keirstead which includes the crest of Long Hill. Numerous small prospect pits have been dug by mineral collectors but no organized beryl mining has been attempted. There are several small quarries on the hill which were worked for gneiss dimension stone many years ago.

Beryl occurs in numerous small pegmatite dikes cutting both the hornblende-biotite gneisses and the small concordant quartz veins associated with the gneisses on Long Hill. The gneiss banding and the quartz veins strike N 17° W and dip 75° E. The cross-cutting pegmatite dikes strike an average N 40° E, and dip 65°-75° SE. The exposed dikes (as seen in some of the old stone quarries) are small, up to 8 feet wide by 40 feet long, and are emplaced in a typical en echelon pattern. Gem beryl (green to blue) appears to be an ubiquitous dike constituent. In some of the better exposures beryl appears to comprise 1 percent of the pegmatite mass. Most of the pegmatites, however, are poorly exposed, showing only in small rubble filled pits where prospectors set off a single dynamite charge. The pits are numerous and widely scattered and, coupled with abundant quartz-perthite pegmatite float on the ridge line of Long Hill, indicate that one or several other pegmatites may be concealed beneath overburden. However, no exploration was attempted to evolve an answer to this question.

Exposed pegmatites are fairly well zoned but zoning is not entirely consistent from one pegmatite to the next.