Spinel was recently added as an August birthstone, sharing this month with peridot and sardonyx. It has long been mistaken for ruby by emperors and monarchs. Many of the famous “rubies” of history were actually spinels.
Until recently, spinel was an underappreciated gem with little consumer recognition. Increasing demand for ruby alternatives rekindled appreciation for spinel’s rich red color and history. In ancient times, southeast Asia’s mines yielded exceptional large spinel crystals, which became the treasured property of kings and emperors, often passing through many hands as spoils of war.
The spinel is often assumed to be other gemstones because it tends to resemble either a ruby or sapphire. In fact, some of the most famous rubies in history have turned out to be spinel. But its distinguishing features, like its octahedral crystal structure and single refraction, are what sets it apart from other gems. Spinel also has a lower Mohs hardness than ruby and sapphire.
Significant deposits of spinel have been found in Cambodia, Myanmar, Sri Lanka, and Thailand. It has also been found in Afghanistan, Australia, Brazil, Madagascar, Nepal, Nigeria, Tadzhikistan, Tanzania and the U.S.
Vivid red is the most desirable color of spinel gemstones, followed by cobalt blue, bright pink and bright orange. The more affordable stones are often those with paler colors, like lavender. You may also find spinel in black, violet blue, greenish blue, grayish, pale pink, mauve, yellow or brown. So many choices!
When shopping for spinel, a good quality stone should have no visible inclusions. The more inclusions, the less valuable the stone. Spinel can be found in various cuts, like octagons, trillions, squares, rounds and fancy shapes, like ovals, pears, and cushions.
Spinel is a good candidate for the title of “History’s Most Underappreciated Gem.” Some ancient mines that supplied gems for royal courts from Rome to China produced spinel, but it was usually confused with better-known stones like ruby and sapphire.
In ancient times, the mines of central and southeast Asia yielded exceptionally large spinel crystals. These fine stones became known as Balas rubies, and some of them were the treasured property of kings and emperors, often passing through many hands as spoils of war. As a result, some of the world’s most illustrious “rubies” are actually spinel.
One of the most famous examples is the so-called “Black Prince’s ruby.” This historic crimson-red gem is set in England’s Imperial State Crown and displayed in the Tower of London. Smoothly polished and roughly octagonal in shape, it was probably mined in the mountains of Afghanistan. It first appeared in the historical records of fourteenth-century Spain, and was owned by a succession of Moorish and Spanish Kings before Edward, Prince of Wales—the “Black Prince”— received the stone in 1367 as payment for a battle victory.
Since then, many other English monarchs—including Henry VIII—have cherished the gem. It’s outlasted them all, surviving fires, attempted theft, and World War II bombing raids, to become—with the Koh-i-Noor diamond—one of the centerpieces of England’s Crown Jewels.
Another large spinel in the Crown Jewels, the “Timur ruby,” weighs over 350 carats. It, too, has a checkered history. Several Persian inscriptions carved into the gem testify to its age.
Modern technology hasn’t helped spinel’s confused identity as far as the general public is concerned. This is due largely to the widespread use of synthetic spinel as an imitation for many other gems. Most customers aren’t even aware that there’s a natural version of the stone.