Spinel (MgAl2O4) is a gemstone that has often been mistaken for ruby. Due to its hardness of 8 on the Mohs scale, spinel is only a shade less hard than ruby, which is 9. Its specific gravity is also similar to ruby. Many famous “rubies” in history were actually spinels. It crystallizes as octahedrons which may appear as twin crystals embedded in rock or deposited as pebbles in gravel (in Myanmar).
This mineral is in fact rarer than ruby now; at one time it was plentiful in India. Now, the main deposits are concentrated in Myanmar, Tajikistan, and Sri Lanka. Spinel in its pure form is colorless, but due to other mineral impurities, it is almost never found colorless, let alone white. The main color forms of spinel are red, pink, light blue, yellow, brown, or even black (called pleonast). The red color of spinel is dependent in large on the amount of iron content. All these different color forms of spinel can mimic many other minerals. Not only ruby, but sapphire, topaz, zircon, and quartz have all been mixed up with spinel at one time or another.
I have a spinel specimen I’ve kept all this while, that I’m showing below in the photo. As you can see, spinels can be a lot like ruby. So much so, that during the 19th century, spinel was indistinguishable from ruby. Only due to more advanced mineral hardness and x-ray tests, was spinel finally recognized as a separate mineral on its own right. Nowadays, there are many synthetic spinels on the market right now which you should be aware of before buying.
Rough, uncut spinel.
The Black Prince Ruby in the British Crown Jewels is a large spinel that was paid to the Black Prince by Don Pedro of Castile as payment for his assistance in putting down a revolt, and except for a brief interlude during the English Civil War, has remained in possession of the British Royal family ever since. It was thought to be a ruby and called a “balas ruby” for hundreds of years.
Spinel crystal from Myanmar.
Spinel is said to help improve physical appearance, and help improve physical vitality. It can be used to enhance (physical) energy during physical activity. I myself used to carry spinel around to help give energy on my daily hikes. Red spinel is especially valued for its action on the root chakra; in terms of metaphysical properties, spinel has a calm and subdued effect. The recommended way to use spinel is to either wear it as jewelry, or carry a few rough crystals in your pocket. Rough, unpolished spinels are not that expensive and costs only a fraction of that of rubies.