Spinel has been mined in central and southeast since ancient times, although these exceptionally large crystals and fine stones were known as Balas rubies. One of the most famous Spinel gems is the “Black Prince’s ruby” which is set in England’s Imperial State Crown and on display at the Tower of London. Historical records show it was owned by several Moorish and Spanish Kings before Edward, Prince of Wales received the stone in 1367. Another large spinel in the Crown Jewels, the “Timur ruby.” It weighs over 350 carats and has Persian inscriptions which attest to its age. It wasn’t until 1783 that mineralogist Jean Baptiste Louis Rome de Lisle identified spinel as a different mineral than ruby.
Spinel is singly refractive with the same physical properties in all directions. The Spinel crystal is said to be so perfect that, in Burma, they are considered “nat thwe” – polished by the spirits. Spinel can be found in a gorgeous range of hues including: intense reds and pinks caused by chromium; oranges and shades of purple caused by a mixture of iron and chromium orange; violet to soft blues with trace amounts of iron; and vibrant blues through trace amounts of cobalt. and red pink as well as all shades of purple, blue, and violet through bluish green.
The most desirable spinel is red, followed by cobalt (almost sapphire) blue, then vibrant hot pink and rich orange.