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Download hereGENERAL DESCRIPTION
Uvite belongs to the group of tourmalines. Uvite is a hydrated borosilicate of calcium, iron and magnesium. It is a rather rare species in comparison of the other members of the tourmaline group (elbaite, schörl...). It is formed in the rocks enriched in calcium that underwent a light contact metamorphism.
The crystals are dark in colour, generally black to brown. They are prismatic, short and generally biterminated. They present a pyramidal summit termination and a flat base. Their faces are striated along the length.
The uvite is well distributed throughout the world, it is known in many deposits such as the province of Uva in Sri Lanka, Serra das Eguas in Brazil, the district of Sasaing in Burma, the Lengenbach quarry in Switzerland or Pierrepont in the State of New York in USA.
There are not deposits indexed in France. Like all tourmalines, the uvite is piezoelectric and pyroelectric. The gemmeous varieties are used in jewellery.
The types of this species are kept in various institutions: Harvard Mineralogical Museum (Cambridge, USA), the Muséum national d’Histoire naturelle (Paris, France), the National Museum of Natural History in Washington (USA) and Royal Ontario Natural History Museum of Toronto (Canada).
HISTORY : Named to recall its type-locality: Uva province, Sweden
Species first described in 1929 by Wilhelm Kunitz (1894-1983), German mineralogist
Type-locality: Uva Province, Sri Lanka
CHEMICAL FORMULA : (Ca,Na)(Mg,Fe2+)3 Al5 Mg(BO3)3 Si6O18 (OH,F)4
CRYSTAL SYSTEM : Hexagonal
COLOR : Brown, light- to dark green, red, black, with color zonations
DIAPHANIETY : Semi-transparent
LUSTER : Vitreous to resineous
STREAK : White, light green
MORPHOLOGIE : Prismatic crystals, isometric, tabular
HARDNESS : 7,5
CHEMICAL CLASS: 3,08
DENSITY : VIII - Silicates
GROUP : Tourmaline
STRUNZ CLASS BEFORE 2001 : 8/E.19-90
STRUNZ CLASS AFTER 2001 : 9.CK.05
