From a parcel of unfamiliar rough to a Smithsonian collection.
Tanzim Khan Malik, founder of Genuine Gems & Jewellery in Bangkok, is credited across the gemological and trade press as the discoverer of Gold Sheen Sapphire™ — the person who first recognised, cut, named, and trademarked this material as a distinct variety of corundum. Here's how that happened, and what's been written about it since.
"They didn't look like much. I was intrigued."
In 2009, with thirty years already in the gem trade and a shop in Bangkok's Silom district, Tanzim Khan was approached by a dealer offering a parcel of rough stones from a remote part of Kenya, near the Somali border. At first glance they didn't look like much — dark, opaque material, unlike any sapphire he'd handled before.
Over several days of experimenting with cutting angles, the right orientation revealed something no one had catalogued in sapphire before: a golden adularescence, moving across the stone's surface as it turned in the light. Convinced there was something genuinely new here, Khan went on to help finance the remaining mining operation and purchased its production.
By 2014, the deposit was exhausted. No further rough has entered the market since — what was mined in those five years is the entire supply that will ever exist.
Khan named the material for its defining feature and registered "Gold Sheen™" as an international trademark.
Independent research into the rarity of Gold Sheen Sapphire is underway, with findings expected to be published in the coming months.
Registered by the Smithsonian.
Before bringing the gems to market, Khan had them examined by laboratories across the gemological trade — GIA, AIGS, GIT, TGL, GRS, Lotus Gemology, AGL, SSEF, ICA GemLab, and IGL among them. Every result confirmed the same thing: a natural, untreated species of sapphire exhibiting a golden sheen not previously documented in corundum.
In 2018, at the AGTA GemFair in Tucson, the Smithsonian Institution's National Gem and Mineral Collection registered Gold Sheen™ as a new variety of corundum and added a sample to its permanent collection — photographed there with curator Jeffrey Post.
Covered in the trade and scientific literature.
Since 2015, Gold Sheen™ sapphire has been the subject of peer-reviewed gemological research and trade-press features. A selection:
Bui, Deliousi, Malik & Corte, "From exsolution to 'Gold Sheen': A new variety of corundum," Vol. 34, No. 8, 2015 — the first comprehensive scientific study.
View PDFGIA, "Update on Spectroscopy of 'Gold Sheen' Sapphires," Winter 2016, Vol. 52, No. 4 — laboratory analysis of 14 stones.
View PDFGIA Gem News International, "Update on trace-element chemical characteristics of golden sheen sapphire," Summer 2018, Vol. 54 — 23 stones analysed at GIA Tokyo.
View PDFGem-A, "Shimmering Sapphires" by Thanh Nhan Bui, Winter 2018, Vol. 27, No. 4 — cover feature exploring colour, transparency, and value.
View PDFICA, "Gold Sheen Sapphires — From Gold Mine to Market" by Cynthia Unninayar, Summer 2018, Issue 38.
View PDFNarudeesombat et al., "Golden Sheen and Non-Sheen Sapphires from Kenya," Gem and Jewelry Institute of Thailand — inclusion and spectroscopy study.
View PDFEach "View PDF" opens the original scan directly for reading — these are shared here as coverage of our own material, with copyright remaining with the original publisher in each case.
Set by designers, worn on the awards stage.
Since appearing at gem shows in Bangkok, Hong Kong, and Tucson, Gold Sheen™ sapphire has been set by David Yurman and featured in pieces by John Hardy and designer Brenda Smith.
A Gold Sheen™ sapphire ring by William Travis Designs won the American Gem Trade Association's Savor Silver Award for Men's Jewelry.
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