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Richard Edwards (left) and Gary Freeman use a pneumatic drill to test for possible extensions of the mineralization in the enor-mous pocket at Mt. Mica. Water, used for dust suppression, creates a fine mist that fills the tunnel.
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An insder's look into gem mining
at Mt. Mica, Maine
By Brendan Laurs
Mt. Mica in southwestern Maine is the United States' first reported source of gem tourmaline. Discovered in 1820, the large granitic pegmatite is famous for occasionally producing beautiful crystals of mostly green tourmaline; fine gemstones have also been faceted in a variety of colors. An ambitious mining venture by Coromoto Minerals began to produce gem-and specimen-grade tourmaline from both open-cut and underground workings in May 2004. (See article by W.B. Simmons et al. in the Summer 2005 issue of Gems & Gemology, pp. 150-163.) Its success is due to their extensive experience with gem pegmatites and the enormous amount of material they have mined to find the tourmaline-bearing pockets.
Mine owners Gary and Mary Freeman, with miners Richard Edwards and Jim Clanin, encountered an enormous pocket at Mt. Mica in July 2005. Freeman invited me and filmmaker Pedro Padua from GIA's Course Development department to visit in August 2005. By this time, a chamber had been excavated within the pocket that measured approximately 11 m long, up to 2.1 m tall and 1.5 m wide.
Photographs of the mining and production appear here and in the Winter 2005 issue of G&G (pp. 357-360). The filming done by Padua will be incorporated into a future video on gem mining to be used in GIA's education programs.
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Gary Freeman carefully removes mud containing tourmaline crystals, fragments of quartz and feldspar. The angular object above his hands is a quartz crystal still attached to the pocket wall. A hose near his left hand pumps out the ice-cold groundwater that seeps into the pocket.
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– Photos by Brendan Laurs. Studio gem photo by Leonard Himes.
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The pocket material is brought to the surface in 5-gallon buckets. Even when filled just halfway, each weighs more than 40 pounds (18 kg).
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This crystal of green tourmaline is shown moments after it was removed from the pocket. The crystal, fractured by natural forces on both ends, would have been worth much more if it was undamaged. The roller coaster of excitement and disappointment is a frequent factor in successful gem mining.
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Jim Clanin and Richard Edwards wash and screen the pocket material to recover tourmaline, quartz crystals and rare pieces of pale pink beryl (morganite). After picking the gems from the top screen, it is flipped upward so smaller pieces can be picked from another screen lying just below it. Several buckets of pocket material can be washed in this fashion every hour.
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Although most of the mined tourmaline was green, these crystals show the range of colors found in the large pocket. White "cleavelandite" (albite) feldspar and purple lepidolite are attached to some of the crystals. The largest tourmaline measures 13 x 13 x 10 cm (about the size of a grapefruit).
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This well-formed crystal of green tourmaline was left on the washing screen after the pocket mud was rinsed away. The shiny striated prism faces are typical for tourmaline. the brown iron staining will be cleaned in an acid bath.
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