Spinel Information

Spinel has been used since ancient times but has often been mistaken as corundum, with the blue verity looking like sapphire and the red like ruby. There are many examples of famous Spinel that were originally thought to be rubies such as the Timur Ruby and the Black Prince’s Ruby which are both in the British Crown jewels. It is also thought that may other European crowns are decorated with what turned out to be Spinels. In the Iranian crown jewels there is the Samarian spinel which is thought to be the world’s largest weighing 500cts.

Also like Corundum, it is found in a wide range of colours some of which are more common than others. The most common colours it is found in is red, pink, orange, violet, purple and blue but it can also be found less commonly in brown, black, yellow, green and near colourless. The colour is determined from the presence of impurities found with-in each stone, with red spinel being coloured by chromium and iron and blue being coloured by iron and occasionally cobalt. Spinel’s also can be transparent or almost opaque.

Natural spinel has a hardness of 8 on the Mohs scale and they are resilient and tough stones, being able to withstand cleaning in a ultrasonic cleaner or being steam cleaned. It is also one of the only species of gemstones that is not commercially heat treated to enhance or change its characteristics. Due to the combination of being singly reflective, fairly inclusion free as well as having a high dispersion spinels optical characteristic are bright and colourful with lots of fire. It is also known that when spinels are cabochon cut they can display a 4 or 6 rayed star.

They are found in granities and metamorphic rocks, often in similar areas to Corundum, in such localities as Burma, Sri Lanka, Cambodia, Thailand, Kenya, Madagascar, Afghanistan, Brazil, Australia, Italy, Turkey and parts of the USA.
It is thought that the name spinel may derive from the latin word spina, meaning little thorn referring to the sharp points of its crystals. However there are also sources that indicate that the name is derived from the Greek word spinter meaning spark referring to the stones fire.

Synthetic spinel has been produced since 1910 it has been used to imitate diamonds and coloured gemstones such as aquamarine, zircon and when coloured with cobalt sapphire. It is synthesized using the same method as synthetic corundum using the Verneuil or “flame fusion” method where aluminium oxide is melted and then allowed to recrystallise. The series of minerals used to synthesize spinel recrystallize quickly thus making it an easy stone to replicate.