Dravite

specimen number:
2262243

location:
Mwajanga, Simanjiro, Manyara, Tanzania

description:
An attractive spray of prismatic dravite crystals, these mostly colorless with attractive blue terminations. In good condition.

The Mwajanga diggings, situated in the Simanjiro District of the Manyara Region in northern Tanzania, represent a unique, localized gemstone locality renowned for producing highly distinct, collector-quality crystals of magnesium-rich tourmaline, or dravite. Geologically, these unusual deposits are hosted within Neoproterozoic-age metamorphic rocks belonging to the Mozambique Orogenic Belt, specifically occurring within highly specialized pockets and lenses bound to regional metamorphic dolomite formations. The primary crystallization of dravite took place under distinct conditions where early-stage fluids precipitated the tourmaline directly alongside sharp natrolite crystals, shifting over time to calcite matrix associations. The resulting dravite crystals occur as well-formed tabular or prismatic crystals displaying a wide range of striking optical properties, including pale yellow-to-colorless zones, rich orangey-brown hues, and highly unusual, sharply defined white chatoyant bands that exhibit a natural cat's-eye effect. Historically, the locality was discovered and opened as a small, artisanal surface excavation rather than a large-scale corporate quarrying operation, with the initial significant mineralogical production entering the international gemstone and specimen market in early 2014. Independent local miners worked the open clay pockets and hand-dug trenches sporadically through the mid-2010s to extract facet rough and pristine reference crystals from specialized zones like the Kamana pit.

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