New Hampshire Plutonic Suite pegmatite, Alstead field. Located near the village of South Acworth.
Refs.: American Mineralogist (1918): 3: 199-200.
US Bureau of Mines Report of Investigation 4410 (1948).
Rocks & Minerals (1949): 24: 594-596.
Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 941.
Hurlbut, C.S., Jr. (1952) Wardite from Beryl Mountain, New Hamphire. American Mineralogist 37, 849-852.
Cameron et al. (1954) Pegmatite Investigations 1942-1945 New England. USGS Professional Paper 255.
Page & Larrabee (1962) Beryl Resources of New Hampshire, USGS Professional Paper 353.
Roy, Walt (1965) Beryl Mountain, South Acworth, New Hampshire. Rocks and Minerals: April 1965.
Seaman (1976) Pegmatite Minerals of the World.
A beryllium mine that produced more than 20 tons of beryl for use in alloying. Supposedly the greatest concentration of beryl in the world, Crystals up to a foot in diameter with a length to six feet have been found, many of which have either a yellowish or white coloration. The white beryl has the highest concentration of beryllium and coloured, more transparent beryl was cast aside due to the fact that it contained iron impurities making refining difficult. Fragments and crystals of this colored beryl are common on the dumps; crystals intact are rare.
An unusual feature of this deposit is the presence of a massive beryl "core" where most of the ore was mined from. Besides beryl, collectable zircon, var. Cyrtolite, is found in feldspar and or quartz as well as between books of mica, making the individual pegmatites radioactive. Some of the cyrtolite is quite radioactive, the best specimens may reach 10,000 cpm using a Gamma-Sensitive DT-590/PDR-56F NaI:Tl scintillometer.
