Gem Pegmatites of Minas Gerais, Brazil: the Tourmalines of the Aracuai Districts
GEM PEGMATITES OF MINAS GERAIS, BRAZIL: THE TOURMALINES OF THE ARACUAI DISTRICTS By Keith Proctor The first article in this series discussed the n the history of gemstones, tourmaline is a latter-day history of gem miningin Minas Gerais from I Cinderella. Whereas aquamarine was known to the the colonialperiod to thepresent, the nature Egyptians over 5,000 years ago, tourmaline was not dis- of granitic pegmatites and derived deposits covered until the mid-1500s, in Brazil. Even then, it was yielding gemstones, and the important mistakenly heralded as emerald. Over a hundred years deposits of aquamarine and other gem passed until, in 1793, it was recognized as a distinct min- beryls. The present article describes the eral species and named for toramalli (from Sinhalese, a major tquqmaline deposits in the Araquaf- Itinga and Ara~uai-Salinasdistricts of term applied to waterworn gem pebbles from Ceylon Minas ~ekais,focusing on the Virgem da gravels) by Dutch merchants (Ball, 1930; Zara, 1973).Be- Lapa mines, the Salinas mine, and the Ouro cause the finest shades of red, blue, and green tourmaline Fino mink Some of the finest green, blue, may resemble ruby, sapphire, and emerald, the relatively red and multicolored tourmalines ever abundant tourmaline has gained popularity as a compara- produced originated from these mines. tively inexpensive alternative to these prized colored gems as well as for its own unique attributes. In the more than 400 years since tourmaline was first ABOUT THE AUTHOR discovered in Brazil, millions of carats of fine gem-quality Mr. Proctor is president ofKeith Proctor Fine Gems, tourmaline have been mined from thousands of granitic a wholesale gem import firm in Colorado Springs, pegmatites in northeast Minas Gerais.
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