Thailand Gemstome

Thailand (formerly Siam) is a major worldwide gem trading, and gem processing or treating center, with the city of Chanthaburi at its hub. Known primarily for its ruby and sapphire, there are several notable gemstones that are mined in Thailand, such as amethyst, aquamarine, garnet, spinel, and zircon.

Gem mining in Thailand occurs in three main regions: Chanthaburi and Trat Province in the south-east, Kanchanaburi Province in the west, and Phrae Province in the north. Chanthaburi and Trat boarder on Cambodia's Pailin region, known for its high-quality ruby and sapphire

Sapphire & Ruby from Chanthaburi

The city of Chanthaburi (Muang Chan), like Ratnapura in Sri Lanka, is one of the famous 'gems towns' (aka City of Gems) of South-East Asia. Muang Chan's (Chanthaburi's) 'weekend market' sells gems from around the world, many of which have been heat-treated in one of Chanthaburi's many gem polishing factories. Gem polishing is primarily a cottage industry in Chanthaburi, with factories spread throughout the city.
  

 

Outside of the city, sapphire and ruby mining in the Chanthaburi Province is located near Aranya Prathet (Aranyaprathet), along the Chanthaburi Aranyaprathet-Poipet Cambodian boarder, 280 km east of Bangkok. The Chanthaburi region in known primarily for mining rubies (Siam Ruby), and secondarily for yellow sapphire, or black star-sapphire. Mining is conducted along ancient river-bank clay and gravel alluvial deposits, using both mechanized mining, and small scale hand-dug pit mining.

Rubies are found at a depth of 3 to 6 feet. Hand digging is easier during the monsoon season when the ground is softer. Mechanized operations use water jets and sluicing to remove mud and clays from the gravel so that sorting can take place. As in Sri Lanka, conical-shaped baskets are used for sluicing, to extract the gems from the gravels and sand.

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Larger mechanized mines in Chanthaburi are the Bon Rai ruby mine and Nong Bon ruby mine, approximately 10 km from the Cambodian boarder. Small-scale pit mining is conducted in the Ban Bo I-Ram, Bo Na Wong, Bo Waen, and Wat Tok Phrom mining areas.

Sapphire & Ruby from Trat Province

The eastern Thai province of Trat is situated just to the south of Chanthaburi Province, bordering with Cambodia to the east, and Malaysia to the south. Until the crash of the ruby market in Myanmar in the 1960s, there was little interest in the darker, lower-quality rubies from Amphoe Bo Rai, in Trat. The Trat Bo Rai ruby mines are mostly hand-dug alluvial open-pit mines, with some mechanized operations. When Cambodia began flooding Trat with rubies, Bo Rai became an overnight ruby boom-town.

                                               

Sapphire & Ruby from Kanchanaburi

Known for its famous "bridge over the River Kwai" and deep-blue sapphire, Kanchanaburi Province is located on the western edge of Thailand, 128 km west of Bangkok. Sapphire and onyx mining in this region occurs at the alluvial pit-mines of the Kanchanaburi Bo Phloi (Amphoe Bo Thoi, Amphoe Bo Phloi, bo Ploi tambon) district, 30 miles north of Kanchanaburi Town. Sapphire in Kanchanaburi's Bo Phloi region was discovered in the early 1900s, and is one of the main sources to this day. Kanchanaburi is known for its deep-blue sapphire, which can have a dark or "inky" appearance.

Sapphire & Ruby from Phrae Province

The Phrae sapphire mines in Phrae (Wiang Kosai), situated along the Yom River, about 550 kilometres north of Bangkok. Phrae is one of the oldest cities in northern Thailand, which was part of Lanna Thai Empire that spans 800 years. The ancient cities of Sukhothai and Chiang Mai are located within Phrae Province, built by the Tai Lue people. The Burmese influence in this region is reflected in the architectural style of the Wat Chom Sawan and Wat Luang Buddhist temples.

Sapphire & Ruby from Pailin, Cambodia

For three decades after the Viet Nam war, the Khmer Rouge kept total control over the Pailin ruby mines, in order to finance its regime. Aggressive mining has severely depleted the supply of Cambodian ruby in recent years.

Heated Material from Thailand

Thai gem-cutters have become experts in the heat-treatment of rubies and sapphire, over the last few decades. As much as 90% to 100% of the sapphire originating from Thailand may have been heat treated, diffusion treated, or both.

Thailand's Muang Chan's (Chanthaburi's) 'weekend market,' and the Trat province rough gem markets sell sapphire heated in Thailand, but originating from Laos, Madagascar, Sri Lanka, Tanzania, and Vietnam.