Like many dealers in the heart of Bangkok’s gem district, Genuine Gems & Jewellery sold a variety of fine coloured stones. Then, one day, life changed forever for owner Tanzim Khan.

“With my shop in Silom and 30 years in the business, I am often approached by dealers who want to sell their gems,” he recalled. “A few years ago, a man from Africa showed me rough stones from a remote location in Kenya. At first glance, they didn’t look like much. I knew they were sapphires, but they were unlike any I had ever seen. I was intrigued.”

Khan took a few samples and asked the man to return in a week. He experimented with cutting the unusual gems and ultimately found the right orientation of the rough to reveal a unique asterism with a golden shimmer. Noting that the sheen “was incredible,” the gemstone dealer decided to investigate the mining conditions in Kenya. As he found them to be above average, he helped the mine owners financially and later purchased the entire production. By 2014, the mine was depleted but Khan had enough rough to satisfy demand for years to come.

“The gems differ from conventional sapphires because they exhibit a gold adularescence caused by the gem’s molecular structure that refracts and reflects light. This creates an iridescence, which gives the appearance of light coming from within as well as shimmering on the surface,” he explained.

Going mainstream

Khan then had to bring his find to market. The first step was having them analysed by various gemmological laboratories, including the Gemological Institute of America (GIA), Asian Institute of Gemological Sciences (AIGS), The Gem and Jewelry Institute of Thailand (GIT), TGL Gem Testing Laboratory, GRS GemResearch Swisslab, Lotus Gemology, American Gemological Laboratories (AGL), Swiss Gemmological Institute SSEF and IGL Labs. “The results all showed the gems to be a new species of sapphire – natural, no enhancement, exhibiting a golden sheen,” he noted.

Next, Khan needed to give the gem a descriptive name reflecting its shimmering colours. He decided on Gold Sheen™ sapphires, now trademarked internationally.

Raising awareness about his gems involved a social media campaign and exhibiting at trade shows in Bangkok and Hong Kong. In 2016, Khan took his new sapphires to the gem shows in Tucson. “It was a good decision. Not only did I sell a lot, but I met many people who share my passion for them,” he said.

Soon, Gold Sheen™ sapphire jewels were seen in collections of established brands as well as boutique designers. Added visibility occurred when the gem was featured in a ring that won the American Gem Trade Association’s Savor Silver Award for Men’s Wear. Today, the gem’s biggest market is the US, followed by Japan and Switzerland, although Hong Kong, South Korea and Australia also appreciate these unusual sapphires.

“Sizes range from a few points to 500 carats, with the most common from 10 to 20 carats. The dust is also requested – for metaphysical purposes,” Khan explained. The most popular cut is cabochon, followed by checkerboard, rose and brilliant. “We can make any cut that enhances the beauty of the stone,” he added.

Prices vary by quality. Commercial grade sells for US$7 to US$15 per carat; good to very good, from US$25 to US$50; fine to extra fine, from US$100 to US$300; and rare, from US$500 to US$1,000. According to Khan, exceptional, large, multicolour transparent gems can fetch US$2,000 per carat. Given the price and quality range, Gold Sheen™ sapphires are ideal for both fine and semi-fine jewellery, he noted.

“As we experimented with the gem, we found more colours. Some exhibit shimmers of blue, green, grey, red, pink and even purple,” Khan revealed.

Most stones have two to three colours, although some have four, making each gem, with their distinctive inclusions, totally unique.

Very recently, Khan found that the gems glow bluish-green or translucent green in UV light. Another surprising discovery is that “some gems are colour-changing.” And, all are untreated. “All Gold Sheen™ sapphires are completely natural, and we can verify their ethical provenance from mine to market,” he remarked.

“This endeavour has exceeded my expectations,” Khan concludes, noting that he continues to work with gemmologists in researching the unusual gems so that the world can fully appreciate the singular beauty of the gold and other colours in Gold Sheen™ sapphires.