Hambergite

Hambergite, named after Axel Hamberg, the Swedish mineralogist, occurs as colorless to yellowish white crystals, but is rarely gem-quality. Brittle, with perfect cleavage, it is very fragile and suitable only for collectors. When cut, it appears like glass, but double images of the back facets may be seen through the table facet due to its high birefringence.

Gem quality hambergite is found in Kashmir (India), and also in Madagascar.

Hambergite Properties

Chemical Composition: 
Beryllium hydroxyborate
Crystal System / Forms: 
Orthorhombic
Hardness: 
7.5
Specific Gravity: 
2.35
Lustre: 
Vitreous
Refractive Index / Birefringence: 
1.55-1.63 / 0.072
Geological Occurrence: 
Kashmir (India), Madagascar
Cuts & Uses: 
Brilliant, Step cut.