Mong Hsu Ruby

Fact Sheet

Location: Mong Hsu is a small town east of Mandalay in upper Burma, or Myanmar. The ruby mines are located on a mountain known as "Red Sand" Mountain.

History: The discovery of rubies in Mong Hsu was first delineated by the Burmese government in July, 1992. A few months later, the stones began pouring in large quantities across the border into Thailand, primarily through the town of Mae Sai in Chiang Rai province, and to a lesser degree into Mae Hong Song. The Burmese territory near Mae Sai is controlled by the Burmese government, while the area opposite the border from Mae Hong Song is the territory of opium warlord Khun Sa, Who heads an army of Shan rebels seeking an automonous state. Today, about 200 +/- buyers from Chantaburi, Thailand vie for the stones in Mae Sai, spending approximately US$8 million a month on Mong Hsu rough, making it the primary material currently available on the Thai ruby market.

Pronunciation: Mong Hsu is pronounced "Mong Shu." Some Thai dealers also call it "Mine Shu," or even "My Shu."

Characteristics: A blue-to-black core distinguishes Mong Hsu rough. Thai burners are usually able to eliminate this core through high temperature cooking. However, the stones generally have a cloudy or "sleepy" appearance, which does not stack up to the finest Mogok material. They often have a "Fluxy" look internally that can cause misidentification as synthetics. The Mong Hsu stones are also susceptible to containing glass-like fillings deep within their fissures--a result of foreign substances used in the heat treatment process combined with the fact that Mong Hsu stones often have a lot of cracks that absorb the substances. Mong Hsu rubies comes in a range of small to very large sizes, with rough stones as large as 30 carats reported.