Spinel

The name "spinel" doesn't conjure up thoughts of romance, or even history. It's not a birthstone or an alternate birthstone. It ranks 22 on the list of anniversary stones, below the lesser-known iolite. But spinel has been around for hundreds of years and, in at least one instance, can boast of its own "crowning achievement."

History and romance. How could spinel have been around for so long and not have any real history or lore? It's a case of mistaken identity. The bright, saturated red color, along with its hardness, confused the best gem experts of the day—so much so, in fact, that the misidentification created an incredible piece of history that spinel now claims as its own.

The most famous spinel in the world is the Black Prince's Ruby, bezel-set front and center on a diamond-jeweled Maltese cross mounted in the British Imperial State Crown. It is, of course, not a ruby, but a rough crystal of red spinel. It's a magnificent stone keeping good company with other magnificent gems. For example, directly below the Black Prince's "Ruby" sits the Cullinan II, a 317.4-ct. cushion brilliant-cut diamond. Atop the crown, in another diamond cross, is the oldest gem of record in the British Crown jewels—a large blue sapphire from King Edward the Confessor, dated 1043. And on the back of the crown is the Stuart sapphire, whose recorded history goes back to 1214 and King Alexander II of Scotland.

According to the legend of the Black Prince's Ruby, written by Leslie Field, author of The Queen's Jewels, the large spinel was first recorded as having belonged to Abu Said, an Arab ruler of Granada in the mid 1300s. In a battle to reclaim the throne, Pedro the Cruel, King of Castile, killed Said and gave the spinel to the Prince of Wales, Sir Edward of Woodstock. Posthumously known as the Black Prince after being buried in an all-black suit of armor, Edward had aided King Pedro in his battle against Said, helping to restore Pedro to the throne. The list of royals who inherited the misidentified spinel included King Henry V, who wore it in his battle helmet. Evidently the spinel was not a particularly lucky gem, as King Richard III was killed while wearing the spinel in the battle of Bosworth in 1485.

The second most famous spinel also is ruby-labeled. The Timur Ruby, weighing 352.5 cts., dates back 600 years to Tamerlane, conqueror of Persia, Afghanistan, and India. The Timur "Ruby" was on display at the Great Exhibition of 1851 when the East India Company presented the spinel to Queen Victoria. It currently is set into a very large necklace of diamonds and rubies that is seldom if ever worn.

Qualities. Spinel's quality grade, like that of other transparent gems, is based on clarity and saturation of color. Traditionally, the more saturated the color—no matter what the hue—the more desirable the gem. Nice, eye-clean, saturated spinels shouldn't be difficult to find. However, the lighter, more pastel colors—especially in larger stones—may reveal some inclusions. Inclusions of tetrahedron and octahedron, which may or may not be eye-visible, can positively identify a gem as a natural spinel and may actually increase a gem's desirability.

Color variations. Spinel's hues are concentrated at the far ends of the visible spectrum, which includes pinks and reds at one end and purples, violets, and blues at the other. Pinks and reds are more desirable, violets and purples less so. Blue spinels are less common. They're especially rare in the more vibrant pure blue hue, which is colored by cobalt. Less expensive blue spinels tend to be less intensely colored—they are colored by iron, and more often modified by green, gray, or violet. Purple, pink, and red spinels can be modified by secondary colors including the less desirable brown and gray.

The finest red spinels in the market today come from Burma. The flame reds are typically orangey red, sometimes with a hint of pink. A pure ruby-red spinel is hard to find. Blue spinels come from East Africa, China, and Viet Nam as well as Burma and Sri Lanka. Sri Lanka produces spinel in all colors but mainly the lighter tones and saturations, including color-change and star spinels.

Enhancement and synthetics. Spinels have, so far, not responded to heat or irradiation. You're likely to encounter synthetic spinel, one of the first synthetic gems ever produced. It has been manufactured inexpensively by the flame-fusion process and is used in school rings and inexpensive jewelry. To identify synthetic spinel, look for tiny white gas bubbles or thread-like inclusions under magnification, crosshatch reaction in the polariscope, or strong fluorescence. Within the past 10 years, spinel also has been produced by the more expensive flux method. The Russian flux spinels are sometimes difficult to identify without advanced gemological testing equipment.

Pricing. Red spinel in fine to very fine quality, with a highly saturated color, can command $600-$1,300 per carat for gems under 5 cts., with some of the newer Burmese stones commanding the higher prices. Vivid "fluorescent" reddish-pinks can range from $300 to $900 per carat. The more pastel pinks are priced slightly lower, with violet and purple-colored gems listed at $150-$400 per carat. Most blue spinels are priced at $200-$600 per carat because of oversaturation or a gray modifier. But because of the obvious difference in color purity and saturation, blues colored by cobalt fetch prices of $2,000 per carat or more.

Care and cleaning. Spinel, which ranks 8 on the Mohs hardness scale, is a durable gem material that makes a nice ring stone. Ultrasonic cleaning should cause no problem for spinel.

Bench repair and setting. Again, nothing unusual to note. However, take the usual precautions to protect the gem from direct heat.

Recommended reading. For more information, see: The Queen's Jewels, by Leslie Field, Harry N. Abrams Publishing, 1997.