Golden sheen sapphire

Coefficient of thermal expansion (5.0–6.6)×10−6/K Gold or Golden Sheen Sapphire is a gemstone variety of the mineral corundum, an aluminium oxide (α-Al2O3). It typically shows a metallic golden colour with common variations being brass, copper and bronze, however metallic blue, green and yellow colouration is also possible. A very rare variation is a metallic red […]