Precious Gem stones production in 1912 Page 77



	1044 MINERAL RESOURCES, 1912.

	deposit. The pegmatites form sheetlike or lenticular masses, and the emerald vein proved to be one of the latter. It had a warped east-west strike, and ran close, to, if it did not join, a bulge or boss of pegmatitic granite encountered in the tunnel in the oast end of the cut. The vein ranged from a seam up to 6 feet in thickness, with a length of about 40 feet and a depth of about 20 feet. It is possible that further work might expose other pegmatite lenses deeper and farther west opening out in the continuation of the seam left where the original vein pinched out. Other veins almost identical in appearance with the original emerald vein were found near by, and some of these are being prospected for emeralds. The pegmatite of the emerald vein was medium to coarse grained, and was composed of quartz and feldspar, part of which was albite, wdth some black tourmaline and a little beryl. A few small irregular microlitic cavities were found, and in these the minerals assumed partly developed crystal form. In some of the pegmatites bluish-green apatite occurs, especially in the mass of pegmatitic granite. A few stout crystals of albite and of smoky and colorless quartz have been found in the pegmatite veins. Some of the quartz contains numerous light-colored needle-like inclusions of actinolite. The pegmatite is partly decomposed, so that some of it is ready for washing on sieves, but some is mined in large blocks, which have to be broken separately and examined for emeralds. So far true emeralds have been found hi only one vein, but the similarity in the association of minerals and of inclosing rocks in the other pegmatites is considered promising. In the opening 90 feet south of east of the cotton-boll pit a pegmatite vein was encountered carrying small, clear, nearly colorless beryl crystals and cylindrical rutile crystals, some of which show brilliant red streaks. The beryl crystals yield very brilliant stones when cut. The part of the vein opened appears to he south of the hornblende hypersthenite area, and the vein will be prospected along its northerly strike to that rock. In the trench 200 feet east of the cotton-boll pit beryl crystals were found in pegmatite at a depth of 12 feet. These crystals were rough in form and of poor quality, with a greenish color. One piece contains some patches of true aquamarine. These beryl crystals ranged from small size up to 2 inches in diameter. The emerald crystals are being cut preparatory to the market. Several fine specimens are still intact. A fire at the emerald mine in April, 1913, destroyed a quantity of the rough matrix specimens and associated minerals, so that now only a few of such specimens are available. AUSTRALIA. A discovery of green beryl and emerald has been reported near Poonah, on the Murchison gold field¹ in western Australia. The occurrence was brought to light through the efforts of H. P. Woodward, assistant government geologist, who assisted in tracing back specimens to then^- source. The crystals have been found scattered over the surface in dusty soil formed by the decomposition of schist country rock. No work had been done at the time of Mr. Woodward's 'visit. The formation has been traced nearly 2 miles in a ¹ Mm. Jour., London, March 29,1913.