(Open to the General Public.)
Isaac Noyes was interested in this pegmatite in the late 1880′s. In 1892 the ledge was opened for the first time and in time, it has become a mecca for scientists and collectors alike, deserving the title of one of the most complex mineralized pegmatites in Maine. Tourmaline was first recorded from the locale about 1904 and over the years the green color found at this location has become known as “Harvard Green”.
Greenwood is a town in Oxford County, Maine, United States. The population was 802 at the 2000 census. The unincorporated village of Locke Mills, on State Route 26 in the northern part of Greenwood, is the town’s urban center and largest settlement.
Purple Fluor-Apatite crystals on albite, collected by Frank C. Perham, Maine.
Maine’s many pegmatite quarries have long been important as commercial sources of industrial minerals, gemstock, and specimens interesting to scientists and collectors. None is more famous than Mount Mica, America’s first gem pegmatite (Hamlin 1895). Mount Mica is located in the town of Paris (Oxford County), 1.5 kilometers east of the village of Paris (fig. 4). Gem-quality elbaite tourmaline was discovered there in 1820 and has been found sporadically ever since. A new era of tourmaline mining began when Coromoto Minerals, owned and operated by Gary and Mary Freeman, purchased Mount Mica in 2003. The mine, which is closed to the public, is now operated year round, weather permitting. This article reviews the history and geology of Mount Mica, describes the recent specimen mining, and investigates the chemical composition of tourmaline. A separate article (Simmons et al. 2005) reports the gemological properties of tourmaline that has been faceted from the recent production.
The discovery of tourmaline at Mount Mica dates to 1820 when Elijah L. Hamlin and Ezekiel Holmes discovered a gemmy green crystal at the base of an uprooted tree near an outcropping ledge (Hamlin 1873, 1895; Francis 1985; Perham 1987; King 2000). After the specimen was identified as tourmaline, many more crystals were recovered from the ledge by Hamlin and Holmes as well as others in the community. Two years after the initial discovery, Elijah’s younger brothers, Cyrus and Hannibal, undertook a more thorough exploration of the ledge by drilling and blasting. They exposed a pocket filled with red and green tourmaline crystals to 8 cm in length (Hamlin 1873). Small-scale exploration continued on the ledge by a number of different people, including Samuel R. Carter who mined unsuccessfully in 1864. Two years later, Ordesser Marion Bowker, owner of the farm on which the Mount Mica pegmatite was located, discovered a large tourmaline pocket. Bowker’s find encouraged Augustus Hamlin and his father, Elijah, to begin work at Mount Mica that continued from 1868 until 1890. Numerous fine specimens of tourmaline and other pegmatite minerals were discovered. In 1871 Hamlin blasted open a large pocket and discovered several large achroite (colorless tourmaline) crystals, including one that was more than 11 cm in length (Hamlin 1895).
Many additional pockets discovered shortly alter this find produced fine gem material, including beautiful multicolored crystals with a dark blue base, followed by a pink zone that grades into colorless, and finally a grass-green termination (Hamlin 1895). In 1881 the Mount Mica Tin and Mica Company was formed with Augustus Hamlin and Samuel Carter as president and superintendent, respectively. They operated Mount Mica until 1890 (Hamlin 1895) (fig. 5).
In 1882 some of the best crystals from the Hamlin and Carter collections were publicly displayed for the first time at a special exhibition at the Academy Hall in Paris Hill. In 1886 Hamlin and Carter opened Mount Mica’s largest pocket to that date. It produced more than fifty small tourmaline crystals in a cookeite and lepidolite matrix. The most valuable specimen was a spectacular green tourmaline crystal 24 cm long and 5 cm wide that was recovered in four pieces. At the time it was valued at $1,000! A faceted portion of this crystal provided the 34.2-carat center stone for the famous Hamlin Necklace (Perham 1987). Much of the material produced was sold to George Kunz of Tiffany & Company who arranged for Hamlin’s collection to be purchased by James L. Garland and presented to Harvard University (Kunz 1892).
From 1890 until 1913, Loren B. Merrill and L. Kimball Stone had the mining rights to Mount Mica. In 1891 they opened a fine pocket with exceptional blue tourmalines (Hamlin 1895). According to Hamlin’s records, by May 1895, Merrill and Stone had opened fifty-nine pockets. In 1899 they uncovered a pocket that yielded a 411-carat, flawless blue-green tourmaline nodule that was part of a crystal more than 20 cm long. A second 584-carat gem nodule found in a later pocket was sold to Harvard professor Charles Palache and is now in the Harvard Mineralogical Museum collection (Francis 1985). In 1904 Merrill and Stone opened yet another very large pocket that produced more than 34 kilograms of tourmaline crystals (fig. 6), including achroite nodules and a single polychrome tourmaline crystal that weighed more than 13 kilograms and was 35 cm tall and over 15 cm wide (Perham 1987). This remarkable crystal was sold and disappeared until rediscovered in a home on Beacon Hill in Boston by Benjamin Shaub in 1961 (Shaub 1987). It is now in the Harvard collection.
Tourmaline mining in Maine began to decline after about 1910, in part because of competition from important new discoveries of high-quality tourmaline in San Diego County, California, and in part because of the collapse of the Chinese tourmaline market. After about 1920, tourmaline production was sporadic at best. Mount Mica was purchased by Howard Irish in 1926 but remained inactive until he began mining feldspar in the late 1940s. Consequently, Mount Mica was not included in the World War II-era study of pegmatites by the U.S. Geological Survey, and a description of this historic pegmatite is conspicuously missing from Pegmatite Investigations 1942-45 New England (Cameron et al. 1954).