Spinel is a gemstone found in greater abundance in Sri Lanka than either corundum or chrysoberyl. Its very abundance makes Sri Lanka the second largest producer of this stone next to Myanmar (Burma). Sri Lankan spinel range from ruby red, pink, orange, shades of reddish brown, purple, blue, bluish green, mauve, greenish black, black to colourless. Apart from the common varieties of spinel are also varieties identified as Ceylonite, Gahnite and Ghanospinel. The occurrence of natural blue spinel coloured by cobalt has been found in Sri Lanka. Cobalt spinel has been found around Rathnapura, Okkampitiya and Embilipitiya.
Basic scientific details of spinel family are mentioned below.

• Chemical Composition - MgO.Al2O3
• Crystal System - Cubic
• Hardness – 8.0
• Specific Gravity – 3.60 | 3.58 - 4.06 (Gahnospinel)
• Refractive Index – 1.712 – 1.725 | 1.725 – 1.753 (Gahnospinel)

Original colours are quite different to alexandrite, very often being violet in daylight and changing to reddish Asteriatedspinels with either four or six rays are also found in the gravels of Sri Lanka. Colour changing ‘alexandrite-like’ spinel has also been found from time to time in this country.