Spinels have historically been confused with rubies. The similarity between the two gemstones colouring has led Spinels to be called ‘Balas Rubies’, or ‘Spinel Rubies’, until the formation of scientific gemmology, when these names were abandoned. The two stones can both range in colour from a pink to deeper red. However, unlike Rubies, Spinels are not part of the corundum mineral group, instead they belong to their own Spinel group. They have a distinct hex-tetrahedral crystal formation: this structure can lead crystals to naturally grow in the form of two pyramids joined at the base: this phenomenon is the same structure as of diamonds. But unlike rubies and diamonds, Spinels are ranked lower on the Mohs hardness scale, with a rating of 8.
The main source of Spinels is Sri Lanka or Burma. The upper region of Burma produces small but vividly coloured stones that often are unearthed with brilliant faces. Such stones are so visually appealing that they have been set from the rough, straight into jewellery without being cut or facetted. Stones with brilliant faces are typically set with a corner of the crystal pointing up to catch and reflect light off the faces diagonal.
Large Spinels feature heavily in historic India Imperial jewellery and Royal Regalia. The world’s three largest examples are included in the British and Russian Crown Jewels. Such stones were often only polished rather than cut and faceted. The Samarian Spinel is the largest spinel in the world, weighing 500 cts and is now part of the Iranian Crown Jewels. The Samarian Spinel, along with a 270 cts spinel, were once the possession of the Mughal Emperor Jahangir before the Persian King Nadir Shah captured the stones in his conquest of India in the 18th century. The proud Emperor Jahangir inscribed his name on the smaller stone, proclaiming to his court that: “This stone shall make my name more famous than the entire dynasty of Tamerlane!”
There are many historic examples of magnificent Spinels, but in contemporary fine jewellery they are somewhat rarely found: Rubies typically being preferred for their livelier double refraction of light.