Siam Precious Gems

Siam Precious Gems is a second-generation gemstone wholesale house based in Bangkok's historic Silom gem trading district. Founded by the Wongchai family in 1992, the business has grown from a single cutting workshop into one of Thailand's most respected colored gemstone suppliers, serving independent jewelers and designers across 30 countries. The company specializes in sapphires, rubies, emeralds, and semi-precious colored stones — sourced directly from mines in Sri Lanka, Myanmar, Colombia, and East Africa. Every stone passes through their in-house gemological team before reaching a buyer, with full certification and origin documentation available on request. Kittisak Wongchai, who took over from his father in 2012, has modernized the business while keeping the family's commitment to fair pricing and transparent sourcing. He personally visits mining regions twice a year and maintains long-term relationships with small-scale miners, ensuring ethical supply chains from mine to market. The GemSurf team visited Siam Precious Gems at their Silom showroom in February 2026, where Kittisak walked us through their grading process, cutting facility, and inventory of over 10,000 certified loose stones.