Pursat — Cambodian Sapphire and Zircon District
Pursat — Cambodian Sapphire and Zircon District
The blue and yellow sapphire deposits of the Cardamom Mountain foothills
Pursat is a province and gem-mining district in western Cambodia, located in the Cardamom Mountains foothills approximately 175 kilometres west of Phnom Penh. The district has produced blue and yellow sapphires, blue zircon, and other accessory gem materials since at least the 1960s, and remains a working source of corundum and zircon in the contemporary market. Pursat material sits in the second tier of Southeast Asian sapphire production behind the better-known Pailin deposits in Cambodia's Battambang province and the historical Burmese, Sri Lankan, and Madagascan sources, but it has supplied a significant volume of commercial-grade sapphire to the regional cutting and trading networks based in Bangkok and Chanthaburi.
Geology
The Pursat deposits, like those at Pailin, are basalt-related sapphire and zircon occurrences associated with the Cenozoic alkali basalt provinces of Indochina. The corundum and zircon were carried to the surface as xenocrysts in basaltic magma, and the modern alluvial deposits result from the weathering of these basalts and the redistribution of the gem material into stream gravels and palaeochannels. The basalt-related corundum chemistry is characterised by relatively high iron content and a generally darker, more iron-saturated blue than the metamorphic sapphires of Sri Lanka, Madagascar, and Kashmir. The zircons from the same deposits are similarly basalt-derived, with characteristic chemistry and inclusion features.
Production and quality
Pursat sapphire production is dominated by blue and yellow material, with smaller quantities of green, parti-coloured, and other coloured corundum. The size range typical of Pursat material is one to five carats, with stones above five carats being less common and stones above ten carats relatively rare. The material is generally darker and more iron-saturated than Sri Lankan or Madagascan sapphire of comparable size, and Pursat blue sapphire often shows the slightly inky or greenish-blue character associated with high-iron basalt-related corundum. Heat treatment is the standard for Pursat material, with the treatment improving colour and clarity and being assumed at the wholesale level unless an unheated determination is documented.
Yellow Pursat sapphire is a smaller portion of the production but is commercially significant; the colour is typically a pure to slightly orange-leaning yellow, comparable to other basalt-related yellow sapphires from the broader Indochinese province (including the Bo Phloi deposits in Thailand and the Bo Rai and Khao Samet deposits also in Thailand). Pursat zircon, particularly the heat-treated blue variety, has been a significant component of the global zircon trade for several decades.
Position in the trade
Pursat material is processed primarily through the Bangkok and Chanthaburi cutting and trading networks, which dominate the international supply chain for Southeast Asian basalt-related sapphire. Cambodian rough is exported through these networks for cutting, treatment, and onward sale into the international markets, with very limited cutting occurring within Cambodia itself. The country's broader gem trade, centred historically on Pailin and now including Pursat and other smaller deposits, is a meaningful but secondary contributor to the global sapphire supply behind Sri Lanka, Madagascar, Australia, and Tanzania.
Origin determination by laboratory report for Pursat material is straightforward in principle — the basalt-related chemistry distinguishes the material from metamorphic Sri Lankan and Kashmir sapphire — but in practice many laboratories will issue an origin attribution at the level of "basalt-related" or to the broader Indochinese province rather than specifically to Pursat. Mine-level provenance for Cambodian sapphire is therefore typically a matter of dealer testimony rather than laboratory determination.
In the trade
For Skyjems, a private dealer with sourcing relationships across the Southeast Asian gem trade, Pursat blue and yellow sapphires occupy a position in the broader basalt-related sapphire category alongside Pailin, Australian Inverell, and Thai material. The pricing reflects the more commercial character of the material relative to fine Sri Lankan or Madagascan sapphire — the iron-saturated colour and the absence of premium origin attribution constrain the price ceiling — but Pursat material in fine quality, particularly larger stones with even colour and good clarity, can present good value for design-led work and bespoke commissions where the cooler basalt-related blue is the desired aesthetic. Lab papers from GIA, Gübelin, SSEF, or AGL are advisable for stones above commercial size.