Precious Gem stones production in 1913 Page 69



	662 MINERAL RESOURCES, 1913—PART II. level a few feet above the lower cuts, but still 18 or 20 feet lower than the summit of the knoll. The country rock is biotite gneiss carrying much black tourmaline near the pegmatite. The gneiss has been strongly folded and crinkled near the pegmatite and accordingly has a variable strike and dip. The pegmatite is very irregular in shape, having a westerly trend across the knoll. It incloses streaks of biotite gneiss, and the surrounding gneiss has been injected by many small lenses and streaks of pegmatite. The pegmatite contains large segregations of gray and smoky quartz, some graphic granite, ortho-clase and albite feldspar, pockets or bunches of mica (both muscovite and biotite), black tourmaline, green apatite, a few red garnets, and numerous beryl crystals. A quantity of mica of good quality was obtained during rnining.' The beryl crystals range up to a foot in diameter and are vari-colored; some are bluish, bluish green, yellowish green, and light and dark golden yellow. Much of the beryl is translucent, and parts of some of the crystals are transparent and flawless so that perfect gems can be cut from them. Small dark golden beryl of exceptional beauty has been cut from clear portions of large crystals. Much of the translucent beryl could be used to advantage for cabochon gems and beads. Beryl Mountain, in the town of Acworth, N. H., has long been famous for the size and abundance of its beryl crystals. According to Mr. Eugene Crossett¹ owner of the prospect, an attempt was made in 1884 to quarry a large beryl crystal here for use as a tombstone over the grave of Emerson at Concord, Mass. Difficulty was experienced in removing a crystal without fracturing and the attempt was abandoned. Later a bowlder of rose quartz was adopted for this purpose. Mr. Crossett states that some specimen beryl was removed at this time and a quantity of feldspar and quartz were shipped for the manufacture of pottery, glass, and sand paper. Beryl Mountain is a steep-faced hill or ridge rising about 200 feet above the road around its base. It has a north-northeast trend and is narrow near the summit. Prospects have been opened on the east side of the northern end about 25 feet below the summit and on the summit above. The work on the summit consists of several pits now badly overgrown by vegetation. The principal work is an open cut or small quarry about 25 feet long, 15 feet wide, and 10 to 12 feet high in the hillside. This cut has a cavern-like face 8 to 10 feet high with an overhanging ledge above. The beryl occurs in a pegmatite mass cutting the mica gneiss country rock. The pegmatite and the inclosing formations appear to strike with the trend of the hill, but no minerals of interest were observed in the outcrop to the south of the prospects. The open. cut has been made in a deposit of mixed oligoclase feldspar and quartz through which are scattered numerous beryl crystals and a little muscovite mica. This deposit is capped by a massive bed of granular sugar quartz mostly pure white or tinted with pink. In places this quartz is glassy and translucent, and some has a pale rose color. The contact between the massive quartz and the beryl matrix is not distinct, but the massive quartz grades into that associated with the feldspar and beryl. Several feet below the massive quartz, feldspar is more plentiful than near the quartz. In an exposure of the quarry face measuring about 16 feet long and 8 feet high 35 large beryls Personal communication, dated South Acworth, N. H., Mar. 2,1914.