S is for Spinel
I like to refer to spinel as the ‘great pretender’. Why you ask? Well, spinel has been mistaken for other important stones throughout history and frankly, it has gotten a bad rap because of it.
Spinel, like some other gemstones, is clear in its pure state. It is a magnesium aluminum oxide created when heat and pressure alter impure limestone. It is often found in the same locations as rubies and sapphires. It was not until 1783 that spinel was declared a separate mineral from corundum (rubies and sapphires).
Spinel’s bad rap came from the fact that many highly regarded rubies and sapphires were later identified as spinel, in the British Imperial Crown, for example. The Black Prince’s Ruby (now known as a spinel) has quite a storied history. The spinel’s reputation is improving, however. As more and more enhancements are made to rubies and sapphires to enhance their color, pure spinel gems are gaining in value and appreciation.
A spinel crystal has eight sides, known as an octahedron. It looks like two four sided pyramids joined at the base. It is highly refractive and is found in a variety of colors depending on the trace elements contained within the crystal structure. Colors include red, orange, blue, purple and even black. A color range can be striking as seen in the photos below. These 32 gems were mined in Vietnam and are now part of the permanent collection at the Smithsonian

Spinel has recently been added as an alternative birthstone for August so if you don’t like green, you now have an alternative. That’s industry marketing for you. The stone facets beautifully and is durable measuring at 7.5 – 8 on the Mohs scale. There is no known toxicity so it is a fairly safe gemstone to work with. I could find no uses for spinel other than as a gemstone.
Red and blue high quality spinels are the most sought after. A 6×9 mm high quality red or blue spinel comes in between $1200 – $3400 depending on the cut, clarity, weight, etc. Still a pricey stone.