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Colored Gemstone
Spinel Steps Into the Spotlight
Mistaken for ruby for centuries, spinel has finally come into its own, fueled by a recent boost in supply, increased consumer awareness and recognition of the gemstone’s appealing attributes.
By Deborah Yonick
Durable, brilliant, more affordable than ruby and available in a variety of natural colors and large sizes, spinel is being touted by color gemstone dealers as an ideal gemstone. Consumers are finally appreciating spinel as more than just a collector’s stone and they are finding it in jewelry stores in an array of fine designs.It has taken a long time for spinel to break out of the shadow of ruby, but current market conditions were ripe for its coming out. Among the factors propelling spinel forward are the rarity and high prices of large, fine ruby and the challenges ruby faces from controversial treatments, says Vincent Pardieu, supervisor, field gemology, Gemological Institute of America (GIA) Laboratory Bangkok, who has studied and written extensively about both stones. Spinel has a history as long as ruby, and since it’s generally mined in the same areas, it often was mistaken for ruby. Many famous so-called “rubies” in crown jewels around the world are actually spinels. Among the most well known is the Black Prince’s Ruby, a 170-carat red spinel that adorns the Imperial State Crown of England in the British Crown Jewels.In all the attention paid to ruby, spinel fell off the radar. “The main problem spinel faced during the past two centuries was the lack of name recognition, as all the promotion went to ruby,” Pardieu explains. “Sadly, spinel all but dropped from sight. With the clear distinction made between ruby and spinel, demand for spinel was lacking, resulting in declining prices and poor consumer awareness. By the end of the twentieth century, spinel had become at best a collector’s stone, at worst a cheap ruby alternative.” Appealing AttributesSpinel certainly has a lot going for it. Unlike ruby, there are few treatments, and distinguishing it from both heated natural and synthetic is straightforward in the lab, notes Pardieu. Spinel is found in an array of natural colors, including blue, purple, gray, orange, brown, pink and red, even an inky green.Chemically similar to ruby, spinel is magnesium aluminum oxide, while ruby is aluminum oxide. Spinel belongs to a large group of composite oxides of similar structure, called the spinel group. “Numerous chemical compositions are possible as these minerals show intense chemical mixing,” Pardieu explains. “Chemically pure spinel is colorless. However, traces of coloring elements like chromium, vanadium, iron and cobalt are found in natural spinels.” Colors more commonly associated with spinel are the red hues, with secondary colors like orange, purple and pink, says Jason Stephenson for the Fallbrook, California–based importer Pala International. He notes that to find pure red spinel is probably more rare than finding pure red ruby. Even scarcer is cobalt blue spinel. Most spinels tend to be of lower to medium saturation, with the noticeable exception of some highly fluorescent spinels from the Namya deposit in Burma, which are typically more pastel than rubies of equivalent hue and tone, according to Niveet Nagpal, a principal in the Los Angeles–based wholesaler Omi Gems. Large spinels, being less expensive than rubies, are usually better cut, as weight retention is less of an issue, Pardieu explains. “With a hardness of Mohs 8, spinel achieves an excellent polish and is ideal for all types of jewelry.” He notes that, like diamond, spinel is singly refractive. “The best spinels have a wonderful transparency, an attribute that is difficult to find with doubly refractive stones, like ruby, which are typically included and silky. It is this combination of good cut and polish, and high transparency and attractive color that make large, clean spinels beautiful.” Out of the ShadowsSpinel’s popularity took off with the discovery of new deposits in Mahenge, Tanzania, in 2007. “For the first time, it was available in quantity, allowing manufacturers to produce sets of matching jewelry,” explains Richard Hughes, Hong Kong–based gemologist and author, who penned the book, Terra Spinel-Terra Firma, with Bangkok-based dealer Vladyslav Y. Yavorskyy. Although the crystals were not entirely of gem quality, with only a thin outside layer classified as gemmy, there were some stunning, clean pink-to-red stones, says Hughes, noting that 10-carat to 50-carat pieces were cut from them. “Their enormous size unleashed a flood of fine red spinel into the world market.” Since Mahenge, Nagpal says he has been able to purchase stones larger than 10 carats and even upward of 20 carats, although presently the area is not producing as much as it was four years ago. But there is still a good amount of inventory in the market, he clarifies, in pink-to-strawberry-red hues. Stephenson considers Tanzania the second-greatest supplier of spinel in the pink-to-red range. Since the 1980s, spinel also has been found in Ipanko and Matombo. “Although production in Tanzania is in flux,” he says, “Tanzania has the potential to be a spinel wonderland.”Nagpal reports a steady supply of lighter pink and purple spinels from Vietnam, near Luc Yen, where mining of rubies and spinels began in earnest after 1990, occasionally unearthing pure red and cobalt blue colors. According to Stephenson, Burma’s Mogok valley was the main source for spinels throughout the twentieth century, and it continues to be the biggest supplier, albeit limited, of pure reds. “We see about a dozen pure red spinels a year in 2-carat to 5-carat sizes, and maybe one or two stones over 10 carats every few years,” he shares, noting that orange-reds, pinkish reds and purple-reds are in steady supply.Spinels also are produced in Tajikistan, at the Kuh-i-Lal mines, the only area where rubies are not found with spinel. Little was known about these mines during much of the twentieth century due to their geographical situation in a closed area of the then-Soviet Union along the Russian-Afghanistan border. “These mines likely produced the Black Prince’s Ruby and other large spinels found in the treasures of Persian, Russian, Mughal and European royalty,” says Pardieu. Following the collapse of the Soviet empire and the end of the Tajik civil war in late 1997, spinel mining was ramped up. Pink has been the dominant color produced there, but recently large red spinels have been found, closely resembling the royal spinels that made “ruby” a household name.
Market Prices With the increase in popularity of spinel, prices have significantly increased, especially for reds. Dr. Michael S. Krzemnicki, head of the Swiss Gemmological Institute (SSEF), believes this is, in part, due to the fact that spinel is typically untreated, accounting for the rise in spinel — often of exceptional size and quality — that has been submitted to the institute’s lab in Basel for certification.Stephenson notes that spinel prices have increased exponentially in the past decade, pointing out that red spinel once priced at $200 a carat wholesale is now $2,000 a carat. “Larger, finer reds and pinks over 10 carats in size could likely fetch $10,000 a carat wholesale — and beyond.” Although spinel prices across the board have been strong, Nagpal says, anything in nice red or blue-to-purple colors is commanding top dollar. “Since there isn’t much available in those colors, people can ask what they want.” Hughes estimates that spinel prices in the past four years have appreciated by more than 500 percent. But he notes that it will be difficult to keep up that pace. “Traditionally, the finest red spinels have been about a tenth of the price of the finest rubies, so if a fine ruby can reach $200,000 a carat, $20,000 a carat is not unheard of for the finest spinel.”Article from the Rapaport Magazine - May 2011. To subscribe click here.
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