Thailand

Thailand's mineralogy is dominated by its world-famous corundum deposits, formed through Cenozoic basaltic volcanism across the eastern and western provinces. The Chanthaburi-Trat gem field, including the historic Bo Rai district in Trat Province, produced the celebrated "Siamese ruby," a deep royal-red variety of corundum whose higher iron content gives it a darker, richer tone than Burmese material. Nearby Bo Welu and Khao Ploi Waen yielded both ruby and fine yellow, green, blue, golden-star and black-star sapphire, while Bang Ka Cha in western Chanthaburi remains a key sapphire source. In Kanchanaburi Province, the Bo Phloi deposit is another classic sapphire locality, notable for corundum hosting rare cobalt-spinel inclusions. These basalt-hosted gem gravels also carry accessory pyrope garnet, sillimanite, spinel, sapphirine and zircon as characteristic mineral inclusions documented in scientific literature on Thai corundum.

Beyond corundum, Thailand's tin belt running along the peninsula through Phuket, Phang Nga and Krabi provinces has historically made the country a major global producer of cassiterite, the principal tin ore, typically recovered from granite-hosted quartz veins, greisen and alluvial placers alongside wolframite, columbite-tantalite, tourmaline, topaz, beryl and fluorite. The Kathu tin-mining district on Phuket Island is historically significant, while the Pilok tungsten-tin district and Rat Buri tin district in Kanchanaburi, along with the Salak Phra fluorspar district, reflect the country's rich metallogenic diversity. Sulfide mineralization featuring chalcopyrite, pyrite, arsenopyrite, sphalerite and galena occurs in association with cassiterite in both northern and southern Thailand, and the Chatree and Akara gold mines in the central plains have produced notable pyrite, andradite, diopside and calcite specimens.

For collectors, Thailand offers a distinctive combination of gem-quality basaltic corundum, classic tin-mineral suites, and attractive secondary minerals such as calcite, quartz, fluorite and mimetite from localities like the Guatomo mine in Yala Province. The scarcity of well-documented, old Siamese ruby and sapphire rough, together with the country's role as a historic global gem-trading hub in Bangkok and Chanthaburi, makes Thai mineral specimens prized both for their scientific inclusion studies and their connection to a centuries-old gem-mining tradition largely worked out and rarely available on today's market.