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Download hereGENERAL DESCRIPTION
Danburite is a calcium and boron silicate. It forms in granites and in metamorphized carbonated rocks. It is associated to other mineral species such as feldspar, axinite, datolite...
Its crystals are prismatic and lengthened, colourless, white and more rarely slightly coloured. They can be terminated by a very acute pyramid.
The most beautiful danburites come from Dal' negorsk in Russia (prismatic crystals of 6 cm), from Anjanabonoina in Madagascar (yellow crystals of 4 cm), fom the Jensen quarry in California (crystals of 6 cm), from Charcas in Mexico (colourless crystals with rosy of 10 cm), from Bolivia (Chapare Viola, Chocabamba), from Mogok in Burma (golden yellow crystals with orange).
In France, only one locality is known to date : Saint Maime in the Alpes de Haute-Provence.
The place of conservation of this type is not known.
Did you know? the crystals of danburite recall those of topaz and form splendid sets of transparent crystals with a sharp vitreous glare.
HISTORY : Named after its type-locality: Danbury
Species described in 1839 by Charles Upham Shepard (1804-1886), American chemist and mineralogist
Type-locality: Danbury, Fairfield, Connecticut, USA
CHEMICAL FORMULA : CaB2 (SiO4)2
CRYSTAL SYSTEM : Orthorhombic
COLOR : Colorless, white, yellow, yellowish brown, greenish
DIAPHANIETY : Transparent to translucent
LUSTER : Vitreux to greasy
STREAK : White
MORPHOLOGIE : Prismatic crystals
HARDNESS : 7,0-7,25
CHEMICAL CLASS: 2,99
DENSITY : VIII - Silicates
GROUP : Danburite
STRUNZ CLASS BEFORE 2001 : 8/J.08-20
STRUNZ CLASS AFTER 2001 : 9.FA.65
