Tag Archives: dravite

Dravite: A Variety of Tourmaline

This article was published in the November issue of Wayne County Gem and Mineral Club News.  Ninety-one dravites from the WCGMC collection were used to wish the members Happy Halloween.

Dravite is a tourmaline within the Alkali Subgroup 1. This means that the X-site in the complex formula below is predominantly occupied by sodium (Na). In the case of dravite the Y site is occupied by magnesium (Mg) and the Z site is aluminum (Al). The boron cyclosilicate mineral is always dark in color, ranging from chocolate brown to almost jet black. Occasionally, there is sufficient chromium in the Y and/or Z site to impart a dark green color. Dravite is most commonly found in metamorphosed limestones and in higher grade mafic schists.

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