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.

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.