These rubies popularity has risen since 1993, after methods to bring out their color were discovered. Their brilliance is especially beautiful under incandescent lighting.
Since 1993, after establishing themselves competitively, rubies from Mong Hsu in Myanmar have replaced Thai rubies as the market leader. The Mong Hsu region is located east of the central Myanmar city of Mandalay. North of Mandalay is Mogok, an area with a long tradition of ruby mining. Ruby rough from Mong Hsu is taken to Thailand and polished in Chanthaburi.

Although ruby had been mined in Mong Hsu since the mid-1980s, the material was brownish and could not be used as such. In time, methods of high-temperature heat treatment suited to these crystals were discovered, and material rivaling the rubies from Mogok began to appear.

Mong Hsu ruby rough contains more imperfections than Thai material, and the chemicals used during heat treatment may penetrate cracks in the material, remaining there in a glass-like form. Such flawed material may initially seem reasonably priced, but its value is low. Few Mong Hsu rubies are notably large or small, with most polished stones apparently falling in the range of 0.3 to 0.5 carat.
The six Mong Hsu rubies shown in the photograph on the next page are typical shapes seen in the 0.5- to 1.0-carat range. Ovals are by far the most common shape seen in today's market, and they are often used as the main gemstones in rings.
These six rubies were chosen for their attractive face-up outlines. With ovals, pear shapes, and heart shapes, the attractiveness of the rounding of the shoulders (corners) is key to beauty. Whether one likes a nearly round heart shape or an elongated heart shape is a matter of personal preference. However, very slight variations in the lines that define the actual heart shape can make the difference between a graceful stone and a boring one. The quality of a gemstone's overall appearance cannot be expressed by numerical values, yet it is critical when judging beauty.

Shortly before ruby mining began in Mong Hsu, rubies from Vietnam had appeared on the market. Yet because of a combination of negative factors such as an influx of synthetic stones, government regulations, and limited mining quantities, Vietnamese rubies are rarely seen today in the trading centers of Thailand. The influx of synthetic stones was not merely a problem for the parties involved, but brought about a general loss in confidence in Vietnamese rubies, preventing that industry from developing.
Ring, Gold
Mong Hsu Ruby 3 pc
0.87 ct
Diamond 2 pc
US $6,000