Throughout history, the Spinel has been confused with Ruby. In part, this is because Spinel is often found in the same deposits and primarily has a reddish color. However, Spinel is a magnesium aluminum oxide, while ruby (corundum) is an aluminum oxide. In addition to red, Spinel also comes in a gorgeous cobalt blue, green, pink and possibly one of the most attractive colors in the entire gem world, a hot pink with an orange tinge.
Spinel is extremely hard with a score of 8 on Moh’s hardness scale and will stand up to normal wear and tear. Spinel makes a great stone for jewelry because of its hardness and luster qualities. Some Spinels are among the most famous gemstones: Among them is the Black Prince’s Ruby and the “Timur ruby” in the British Crown Jewels, and the “cote de Bretagne”, formerly from the French Crown jewels.
- MINERAL: Spinel
- CHEMISTRY: MgAl2O4
- COLOR: red, orange, pink, purple, blue, black
- REFRACTIVE INDEX: 1.718
- BIREFRINGENCE: none
- SPECIFIC GRAVITY: 3.60
- MOHS HARDNESS: 8