Chanthaburi Gem Market Data.

Stone, source, and craft

Chanthaburi is a province in eastern Thailand and the name of its main city. In gem history, the name means more than one market hall. The trade is centered on Si Chan Road, also written Sri Chan Road, and nearby lanes such as Trok Krachang. Thai public sources call the area an International Gem Market. They also use names such as Gem Road or Jewelry Road. These names point to a whole trade district, not one fixed exchange.

The Thai street name is ถนนศรีจันทร์. English sources spell ศรีจันทร์ in more than one way. Tourism Authority of Thailand uses Sri Chan Road. Other trade sources use Si Chan Road. Both names refer to the same street in the sources reviewed here.

Chanthaburi first became a gem center because stones occur in the region. The Chanthaburi-Trat field is tied to old basalt flows. These rocks carried sapphire, ruby, zircon, and other gem material. GIT lists old sapphire areas around Khao Wua, Khao Ploy Waen, Bang Kacha, and nearby sites. GIA field work also records basalt-linked sapphire at Khao Ploy Waen and Bang Kacha.

Mining is only the first part of the story. Local gem output fell over time. The city did not lose its place in the trade. GIT says the modern industry uses much rough that comes from other countries. GIA makes the same broad point. Bangkok and Chanthaburi stayed key centers for cutting, heat treatment, and trade even after the main Thai deposits lost much of their old output.

Trade, treatment, and testing

This shift is central to Chanthaburi. A mine depends on what is in the ground. A craft center can keep working on stones from far away. Chanthaburi kept the skills, tools, dealer links, and trust built during its mining years. Those assets let the city work on rough from Africa, Sri Lanka, Myanmar, and other sources.

Local history gives cutting a key role. GIT links part of the early craft story to Gula or Shan people who came into the area. Its account says they helped teach local people to cut and polish stones. GIT also describes a change from simple cabochon work and foot-driven tools to modern faceting. Much of the work still rests on hand skill. Parts of this story come from local and oral history, so they are best stated as GIT's account rather than as one proven start date.

The craft also spread through homes and villages. GIT describes cutting and polishing as family and local work in parts of Chanthaburi. That helps explain why the city could keep its role when rough began to come from abroad. The key asset was not just a mine. It was the skill to sort, cut, polish, treat, match, and trade stones.

Heat treatment is one of the city's best-known skills. Thai and foreign gem sources both describe Chanthaburi as a major place for heating ruby and sapphire. GIT gives a central place in this story to Sammuang Kaewwaen. Its account says he saw how heat could change gem color and later ran tests with furnaces. A large fire in 1968 is part of that local story. GIT says he went on to develop gas-furnace methods and work with rough from abroad.

The claim needs a clear limit. People heated gems long before modern Chanthaburi. It would be wrong to say the city invented all gem heating. The stronger claim is that Chanthaburi became a major modern center for corundum heat treatment. GIT also credits Sammuang Kaewwaen with an important local step in that modern craft. GIA's older work supports the wider point. By 1982, it described heat treatment as a major Chanthaburi industry.