Spinel, So Similar To The Ruby
Hard, variously colored mineral, having usually octahedral crystals and occurring in igneous and carbonate rocks.
The red variety is valued as a gem and is sometimes confused with ruby
Red, pink, orange, violet, blue, black colors. Hardness: 8 on Mosh scale
Spinel is associated with ruby in many areas where it is mined, and this is the reason why it has been confused with it for a very long time. Many famous rubies in crown jewels are in fact spinel.
One of the most fascinating gemstone in the world is the «Timur ruby» which is a red spinel weighting 361 carats, that is cut in cabochon and named after Tamerlain, the Tartar conqueror, who was one of his owners. This stone has the names of its former owners engraved upon it, and some of them are the same with previous owners of the famous Kohinoor diamond. The Tamerlain is now owned by Queen Elizabeth of England.
Another famous historical spinel set in the British Crown Jewels is the «Black Prince’s Ruby». This cabochon of an estimated weight of 170 carats, was worn on the battle helmet of Henry V during the battle of Azincourt in 1415.
A faceted red spinel of more than 400 carats belonged to Empress Catherine II of Russia, and is now part of the Russian Treasure in the Kremlin.
The origin of the name spinel is unknown. It may be a derivative of the Latin word «spinella» or from a Greek word meaning spark, in reference to the bright red or orange color of some crystals.
Spinel owns his color to chromium, for the red to orange stones, to manganese for the violet and to iron for the blue variety. Occasionally, a color changing variety called « alexandrite like spinel » can be found; its color turns from a light gray blue in daylight to a light purple under artificial light.
Another extremely rare variety is the attractive cobalt blue spinel, seen only in small sizes in some mineral collections.
Spinel was formed in the geological process of contact metamorphism associated with intrusions of molten rock masses. This is the same process which produces rubies and sapphires. Since both spinel and corundum are durable materials, they occur together in the gem deposits.
In addition to Myanmar (formerly Burma), well known for the red to orange varieties, spinel is mined in Sri Lanka, Thailand, Afghanistan, Brazil, Vietnam, Turkey, United States and Nigeria.
Even if in the past large spinels were available, nowadays, cut stones over ten carats of good color are very rare.
The most highly prized colors in spinel are intense red to purplish red, and «hot» pink with a tinge of orange. The other colors, except for the light-violet and purple, tend to be too dark or too gray.
Generally, spinels are more flawless than the corundum gems, therefore visible cracks or flaws reduce considerably their value.
Many commercial or «native» cut spinel tend to be too shallow. This is due to the fact that the best crystals often occur in flattened octahedral and twinned stones.
When choosing a spinel the most important factor to consider is color.
Spinel prices are really high and are getting higher and higher…..
Nevertheless, always bare in mind that all stones are fragile! even the diamond ….
See the interesting article from le gemmologue about the most expensive spinel ever sold! 30 000£ / carat!