DANBURITE
Class : Silicates
Subclass : Tectosilicates
Crystal system : Orthorhombic
Chemistry : CaB2(SiO4)
Rarity : Rare
Danburite is a rare pneumatolytic mineral formed during the injection of pegmatitic magmas into limestones or dolomites. It can also have an hydrothermal origin in metalliferous veins and alpine clefts. It owes its name to its locality of discovery : Danbury, Connecticut, USA. It is generally elongated and terminated prismatic crystals reminiscent of topaz. Transparent to translucent, it is mostly colorless to white, sometimes yellow to brown, pink, or more rarely orange or purplish. The danburite is a mineral that is sometimes cut in faceted gemstones for jewelery but it is still more a stone reserved for the collection.
Main photo : Danburite from La Aurora Mine, Charcas, San Luis Potosi, Mexico
Danburite in the World
Danburite in France
In France, danburite has been reported at St-Maime in the Alpes-de-Haute-Provence where it is found in pyrometamorphic rocks.
Fakes and scams
Can be easily confused with topaz especially when cut because the refractive index of these 2 species is very close.
Hardness : 7 to 7.5
Density : 2.93 to 3.02
Fracture : Subconchoidal to irregular
Trace : White
TP : Translucent to transparent
IR : 1.630 to 1636
Birefringence : 0.006
Optical character : Biaxe (+/-)
Pleochroism : None
Fluorescence : Blue to green-blue
Solubility : Hydrochloric acid
Magnetism : None
Radioactivity : None