Granite pegmatite in the Oxford pegmatite field. Mount Mica is the second oldest elbaite occurrence in North America, after Clarkes Ledge Quarry, Chesterfield, MA. Mount Mica was found in 1821 by two professional men: one a doctor of medicine, Ezekiel Holmes, and one a lawyer, Elijah Hamlin. The day following the discovery was marked by a surprise early snowfall preventing further exploration until Hamlin's younger brothers drilled and blasted the ledge in the summer of 1822.(Although there are numerous reports which cite Augustus Hamlin's histories of the locality claiming an 1820 discovery, the date is incorrect for many reasons and the actual snowfall date is now known.) Mount Mica is a LCT class granite pegmatite.
The first Rose Quartz crystals known in the world were found at Mount Mica Quarry about 1913-1915. The second locality for genuine rose quartz crystals in the world, the Dunton Gem Quarry, Newry, produced it's first crystals in 1927. A third world locality was discovered in 1942, at the Rose Quartz Crystal locality, also in Newry. Rose Quartz crystals were not known in Brazil until 1958.
It is particularly interesting that some pink Mount Mica tourmaline fluoresces blue, but that property is not so widespread as the fluorescent tourmaline of the Dunton Quarry, Newry (q.v.). Fluorescence is not a property that can be unambiguously used to differentiate Mount Mica tourmaline from mislabeled tourmaline.
Refs.:
King, V. and Foord, E., 1994, Mineralogy of Maine, v. 1.
King, V. and Foord, E., 2000, Mineralogy of Maine, v. 2.
http://www.coromotominerals.com/index.html [mine owner]
84 entries listed. 62 valid minerals. 3 type localities (valid minerals). 11 erroneous literature entries.