Bangkok Silom & JTC

Silom, in Bangkok's Bang Rak district, is the world's coloured-stone trading floor — the densest concentration of gemstone dealers, cutters, and exporters anywhere, clustered around Silom and Mahesak Roads and anchored by the 59-storey Jewelry Trade Center.

The scale of Thailand's role is hard to overstate: by trade reckoning, around 90% of the world's rubies are cut and traded here, more than 80% of the world's coloured stones are processed in the country, and Thailand ranks as the world's second-largest exporter of corundum — the ruby-and-sapphire family.

Its defining edge is treatment. Thailand's mastery of the heat treatment of coloured stones is unrivalled, and it is what draws rough corundum from Myanmar, Sri Lanka, East Africa, and beyond to Bangkok to be transformed, certified, and traded onward. Stones arrive from across the world and leave through Silom.

It is a working trade district rather than a heritage quarter — dealer offices, cutting rooms, and labs stacked into towers. A caution for visitors: Bangkok is also notorious for gem scams aimed at tourists, so the real trade runs on established dealers and independent certification.