Gold Sheen Sapphires -
Revisiting this NEW SPECIES
Discovered in a remote part of Kenya about a decade ago, a new species of sapphire first came onto the market in 2014. Realizing the potential of these rough gems when he first saw them, Tanzim Khan, a Bangkok-based gem dealer, purchased the mine's entire production. Because of their unusual bronze sheen that exhibits a shimmering gold effect, with colorful overtones, Khan named (and trademarked) this new gem "Gold Sheen Sapphires." Now six years later, we take a look at the evolution of these unusual gemstones.
By Cynthia Unninayar
All images are courtesy of Genuine Gems & Jewellery, unless otherwise specified.
As word began getting out about this new find in 2014, Khan took his new gems to the trade shows in Bangkok and Hong Kong. He also began a social media campaign to raise awareness of these shimmering stones.
Because of their uniqueness, the new sapphires began drawing interest in the trade. Cap Beesley, of New York-based ARD Analytics, was one of the first, in 2014, to describe the new stone as “a unique bronze colored sapphire that exhibits a shimmering gold effect juxtaposed against a chocolate brown backdrop…This new material with its unique sheen, color and geometric patterns offers lots of creative options for designers, jewelers and manufacturers at a reasonable price…It promises to be an interesting addition for designers looking for a unique gemstone option…”
The Gemmological Association of Great Britain was the first to publish an in-depth analysis of these shimmering sapphires, with an article in the Journal of Gemmology (34(8), 2015, pp. 678–691). They found that the gemological properties of the “Gold Sheen sapphires are consistent with typical corundum…The sheen effect in these sapphires originates from the simultaneous reflection of light from the oriented network of exsolved hematite-ilmenite inclusions.”
In 2016, an Update On Spectroscopy Of “Gold Sheen” Sapphires was published in GIA’s Gems & Gemology (Winter 2016, Vol. 52, No. 4), which described the analysis of fourteen gold sheen sapphires of various shapes and cuts by GIA’s laboratory in Bangkok. “The samples had yellow and green to blue body color, were transparent to translucent, and weighed 1.06 to 97.69 carats…” Among the physical properties was “an abundance of hematite/ilmenite platelets."
Also in 2016, with interest about the sapphires continuing to grow, Dominic Mok, founder and principal of AGIL (Asian Gemmological Institute Laboratory) gave a seminar on the Gold Sheen variety of sapphires to a packed audience in Hong Kong.
In addition to exhibiting in trade events in Bangkok and Hong Kong, and more people asking about the new sapphires, Khan decided to exhibit his gems in Tucson in 2016. “It was a good decision,” he confides. “Not only did I sell a lot of stones, but I met a lot of people who share my passion for them.”
Awareness of Khan's sapphires increased during Tucson's world-renowned gem shows and he began receiving calls from a number of designers and brands interested in his shimmering stones, including “representatives from David Yurman and John Hardy, as well as several smaller designers,” smiles Khan. Sometime later, he was delighted when a Gold Sheen™ sapphire ring designed by William Travis Jewelry won the American Gem Trade Association Savor Silver Award for Men’s Wear. Some time later, David Yurman featured Gold Sheen™ sapphires in a variety of jewels. John Hardy is in talks for specific custom cuts. U.S.-based designer Brenda Smith has devoted a collection to the Gold Sheen, which she displayed at the AGTA 2018 in Tucson. Today, other designers are also showing interest in these unusual gemstones when they visit the booth of Genuine Gems & Jewellery in Tucson, Hong Kong, Las Vegas and Bangkok during 2020.
When Khan started cutting the sapphires, he obtained maybe 30% useable gems, but after years of experimentation, he was able to get 90% in commercial grade and 10% as fine gems. “As we continue to cut and experiment, we are finding more colors. On top of the gold, the stones exhibit sheens of blue, green, gray and pink. Occasionally, but rarely, we find red and purple.” Most gems have two to three colors, but a few have four.
A few rare gems vividly emulate the flashing and folding colors and undulations of the Aurora Borealis lights in the northern night sky, leading Khan to call this the Aurora Effect.
When asked if, as part of his experimentation with cuts and shapes, he has ever tried to enhance the sapphires in any way, Khan replied that he had experimented in the beginning with heating, but that the process only diminished the sheen effect. “All of the stones we produce are natural, unheated and unique,” he insists.
Among the cuts, the most popular is the cabochon, although some countries seem to have a preference for the checkerboard or the rose cut—the preferred cut of designers in the USA. Other cuts that are being demanded include the brilliant cut, and various shapes, including ovals and flat geometric cuts. “We can do any cut that enhances the beauty of the stone,” explains Khan.
Another advantage of the Gold Sheen sapphires is that provenance is transparent. “They come from only one place and now the mine has been depleted. There are no more. We know the workers were treated well, so buyers can be confident that the beautiful gem they just purchased was sourced in an ethical transparent manner.”
Khan also explained that he has been asked by many people to sell some or even all of the remaining stock of rough, but that he is not interested. As his business grows, he is investing more into creating an even greater marketing infrastructure for Gold Sheen. This includes coming out with a line of "Demi-Fine Jewelry" using these shimmering gems set in vermeil in original and affordable designs as well as higher-end pieces.
“You know,” he concludes, “This endeavor has exceeded my expectations. I cannot rest on my laurels, however. There is still much work to be done to get the word out about Gold Sheen so that others may also appreciate its singularity and beauty.” (goldsheensapphire.com)
Tanzim Khan (right) with Jeffrey Post, curator of the National Gems and Mineral Collection at the Smithsonian Museum in Washington DC. The Smithsonian has registered Gold Sheen™ as a new variety of corundum and now has a sample in its collection. (Photo taken at the Smithsonian exhibit at the AGTA GemFair in Tucson, 2018)