Located on Isinglass Mountain. First commercial mica mine in U.S. (1803). Mined for feldspar beginning in 1912, and later for beryl as well. New Hampshire Plutonic Suite pegmatite, Grafton field.
Collecting possible after paying fee ($20 per adult in 2006).
Ref.: 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: 876, 914, 986.
www.rugglesmine.com
