Spinel

Spinel is the magnesium and aluminium member of the larger spinel group of minerals, with the formula MgAl2O4 in the cubic crystal system. The name comes from the Latin word spinella, a diminutive of spine, in reference to its pointed crystals. It crystallizes in the isometric system, commonly as twinned octahedra, has a hardness of 8, and may be colorless but usually comes in shades of red, lavender, blue, green, brown, black or yellow. Some spinels are among the most famous gemstones, including the Black Prince's Ruby and the Timur Ruby in the British Crown Jewels. In this atlas it is the mineral species that spinel gemstones record.

Spinel is the magnesium and aluminium member of the larger spinel group of minerals, with the formula MgAl2O4 in the cubic crystal system. The name comes from the Latin word spinella, a diminutive of spine, in reference to its pointed crystals. It crystallizes in the isometric system, commonly as twinned octahedra, has a hardness of 8, and may be colorless but usually comes in shades of red, lavender, blue, green, brown, black or yellow. Some spinels are among the most famous gemstones, including the Black Prince's Ruby and the Timur Ruby in the British Crown Jewels. In this atlas it is the mineral species that spinel gemstones record.