The stone that spawned the science of gemology - Spinel July 26, 2015 15:36
Long ago every bright red stone was thought to be ruby and deep blue stones were thought to be sapphires. Spinels, which come in every color from red to blue, spawned the birth of the science of gemology due to the need to distinguish it from ruby and sapphire.
Spinels are one of the greatest imposters in jewelry. Many were labeled as rubies and can be found in royal jewelry collections around the world. Once, spinels were called Balas rubies. One of the most famous examples of a spinel "ruby" is found in the British Imperial Crown (housed in the Tower of London) where the Black Prince's "ruby" is actually a 170 carat crimson-red spinel. You can find more information about the crown jewels of the British Monarchy at the official website of the British Monarchy.
The spinel is a favorite among gem dealers and collectors and can be found in shades of red, pink, orange, blue, purple, yellow and black. Bright red and blue spinels are the most valuable and inclusions in these colors are more accepted than in the other colors.
Although the bright red and deep blue spinels are rarer than rubies and sapphires, it remains an affordable stone. Spinels cost a fraction of the price of an equivalent size and quality ruby or sapphire. But, the spinel can be every bit as beautiful as either ruby or sapphire, so it is a great stone to own at a reasonable price.
Spinel ranks an 8 on the Mohs scale which means it is quite hard. As comparison, sapphire and ruby rank 9 on the scale and diamond is alone at 10. It is quite hard to scratch a spinel with most gems other than diamond, corundum or topaz.
Spinels were one of the first gems to be manufactured in a lab. The synthetic stones are produced by sifting aluminum oxide through a hot flame and melt upon a rod that is rotated to collect the material (the Verneuil method). The result is a large single crystal of spinel. Some of this spinel is destined for synthetic jewelry, but much (or most) is used in industry where hard materials are needed.
More interesting topics to come in future blogs.
Hope your days sparkle like our gems!