Spinel is a gemstone that is often confused with Ruby and Sapphire. Spinel is only identified as a separate gemstone in 1783 by Mineralogist Jean Baptiste Louis Rome de Lisle, it is then named Spinel, after ‘Spinella’, which is the Latin word for spine, in reference to its sharp crystal structure. Spinel is one of the birthstones of August.
History & Lore
The biggest Spinel ever is the Samarian Spinel, weighing at 500 cts, it is part of the Iranian Crown Jewels, named after the ancient Hebrew city of Samaria. This spinel was also at one time mistaken for a Ruby, which is similar to what may be the most famous Spinel in the world, The Black Prince Ruby. Being the showpiece of Britain’s imperial state crown, the Black Prince Ruby is probably one of the most famous stones in the world, except that it is not a Ruby. It is actually a Spinel weighing at 170 cts.
Also another famous gemstone owned by the British Royal Family, the 352.5 cts Timur Ruby, is also a Spinel. In fact, many of the famous Rubies and Sapphires, were Spinel, this is not so surprising considering Spinel comes in a variety of colour and is often found alongside Corundum.
Spinels comes in a variety of colours, red, pink, orange, purple, blue and black. The highest valued Spinels are red and pink and the very special cobalt blue Spinel (see collector’s variety section below). The most desired colour in the market for red Spinel is known as the Jedi Spinel, where its colours resemble the red laser sword in the famous movie, Star Wars. Prices of Spinels can differ vastly depending on colour, with the best reds possibly going for over tens of thousands per carat. The top 3 current market prices of Spinels by colour, is vivid red being the most expensive, cobalt blue Spinel right after and then followed by hot pink Spinel.
Spinels generally are much less included than Rubies and Sapphires, and often are expected to be eye clean. Included Spinels that are eye visible, trade at a considerably lower price than eye clean Spinels. Inclusions in Spinels are sometimes good as it may tell origin or certify that this is a natural Spinel.
The most commercially important mine these days for Spinels are located in Burma and Sri Lanka. Newer mines such as those in Madagascar and Tanzania are also increasingly very popular, which you might have heard the term Mahenge Spinel from Tanzania. Mahenge Spinels generally has colours that slightly resembles those in a fine Padparadscha Sapphires. Jedi Spinels on the other hand, generally comes from the Burmese mines. There is also another notable origin among others, that will be the Luc Yen mine in Vietnam. Luc Yen mine is the most famous mine producing one of the rarest gems in the world, the Cobalt Blue Spinel which has a distinctive electric glow to it. The Tajikistan mines, although now producing mostly low quality Spinels was a historically important source, with the famous Black Prince Ruby and Timur Ruby both from Tajikistan.
Cobalt Blue Spinels are blue Spinels that is coloured by the element cobalt. Violet to blue spinel can be colored by iron, whereas rare vibrant blues owe their saturated color to cobalt. Technically all blue Spinels that are coloured by cobalt can be called cobalt blue Spinels but the term usually describes the Spinels with a neon tone. This factor is why some experts only want to consider Luc Yen cobalt Spinels as the true cobalt Spinel as those found in Luc Yen exhibit those colours. Spinels with the Sapphire like colours coloured by cobalt normally comes from Burma, and darker more purplish stones are from Sri Lanka. These are also considered cobalt Spinels by many labs, but they do not trade at prices at which buyers are willing to pay for Luc Yen Spinels.
Do note that in the trade, many dealers try to pass off normal Spinels as Cobalt Spinels by using cobalt diffusion treatments to alter its colour. These are often marketed as Cobalt Blue Spinels, rather than Blue Cobalt Spinels. Be careful with the play of words that some dealers may use and we only recommend purchasing these stones that comes with certification.
Some spinels also exhibit asterism, which is also known as the star effect. It is very rare for Spinels above 5 cts to display such effects.
Spinels are known to be generally free of treatments. It is true that most of the time Spinels are completely natural but new treatments have also been observed. Heating is one of the treatments, originally thought to be ineffective as it does not improve the colour of the Spinel like it does in Corundums, but it has been proved to help clarity in some Spinels. There is also beryllium heating done to produce blue Spinels which passes off as cobalt Spinels, and cobalt diffusion treatments. This is why we only recommend all purchases to be from trusted dealers who disclose all information, or with certifications from major labs.
Synthetic Spinels are readily available and used extensively in costume jewellery. Although they are not as widely used as synthetic Rubies and Sapphires, they are still one of the most used synthetic gemstones. They can be produced via flame fusion, which is one of the cheapest ways to produce synthetic gemstones. Synthetic Spinels are also used to imitate other gemstones, more commonly in a synthetic Spinel triplet, imitating gems such as peridots.
With a Mohs scale rating of 8, Spinels are durable gemstones for jewellery so long as it’s treated with care, as required by any gemstones, to prevent against scratching and hard knocks. Cleaning of Spinels should be done with warm soapy water and a soft brush.