Spring 2000, Volume 36, Issue 1

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Purple to Purplish Red Chromium-Bearing Taaffeites
Karl Schmetzer, Lore Kiefert, and Heinz-Jürgen Bernhardt

Gemological, microscopic, chemical, and spectroscopic properties are given for eight purple to purplish red chromium (Cr)- and iron (Fe)-bearing taaffeites and, for comparison, two grayish violet Fe-bearing but Cr-free samples. The eight purple to purplish red stones represent the largest sample of this extremely rare (i.e., Cr-bearing) variety of taaffeite that has been included in a single study; these taaffeites contain up to 0.33 wt.% Cr2O3, 2.59 wt.% FeO, and 2.24 wt.% ZnO. The purple to purplish red color is a function of the relative amounts of Fe and Cr present. Apatite and zircon crystals are common inclusions in taaffeite. Also present were healed fractures that consisted of negative crystals with multiphase fillings that contain magnesite. Photo by John Parrish

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