Uvite (CaMg₃(Al₅Mg)(BO₃)₃Si₆O₁₈(OH)₄) is the calcium-magnesium variant of the tourmaline group, completing the major-species coverage alongside Schorl (Fe), Elbaite (Li), and Dravite (Mg). It is named for the Uva Province of Sri Lanka, its type locality. Uvite typically forms short stubby prismatic crystals — often with characteristic hemimorphic asymmetry visible at terminations — and a brown to dark green color that distinguishes it from Schorl on physical inspection.
Key Facts
- Mohs hardness 7–7.5.
- Trigonal symmetry; signature triangular cross-section visible at terminations.
- Stubby prismatic crystals are diagnostic — different habit from Schorl/Elbaite’s long prisms.
- Color brown to dark green; rare yellow-brown gem-quality varieties known.
- Forms in metamorphic dolomitic marbles and calc-silicate skarns — Ca-rich genesis distinct from Schorl/Elbaite pegmatites.
Notable Localities
Uva Province (Sri Lanka) is the type locality. Brumado (Bahia, Brazil) produces gem-quality green Uvite. Yinnietharra (Western Australia) yields metamorphic specimens.
Found at these Localities
- Eastern Brazilian Pegmatite Province (巴西东部伟晶岩省)
