Ruby Round Cut Stone, 6mm

Ruby is the hardest mineral after diamond. However, the hardness varies in different directions meaning it has certain preferred directions of parting. Because of the brittleness, care must always be taken when cutting and setting. As they are a rough stone, ruby appears dull and greasy but when cut, the list can approach that of a diamond. Heat treatment is commonly used to improve their colour. 

Shape: Round 

Size: 6*3.1 mm

Weight: 0.20 grams

Colour: Red / Pink

Moh's hardness: 9

Density: 3.97 - 4.05

Cleavage: None

Refractive index: 1.762 - 1.778

Dispersion: 0.018 (0.011)