Black Star Cabs, Oval - 7 x 9mm

Black star is also known as black star sapphire/diopside and is a type of aluminium oxide.  When cut into a dome shape it reveals a star feature. When cut with a flat top a golden colour is revealed. Common deposits are found in Russia, Pakistan, South Africa, Austria, Brazil, Italy, North America, Sri Lanka and Finland but most commonly India.

Shape: Oval

Size: 7 x 9mm  

Height: 3.6mm

Weight: 0.6grams

Colour: Black

Moh's hardness: 5.5 - 6.5

Density: 3.25 - 3.55

Cleavage: distinct/ good on

Refractive index: 1.665 - 1.73

Dispersion: Weak to distinct