Chanthaburi: Thailand’s Sapphire and Ruby Refinery

All data is Abstracted from https://preciouscarats.com/blogs/know-about-thailand-gemstone-hub/ check this out highly recommended.

Where Is Chanthaburi?

Located around 250 km southeast of Bangkok, Chanthaburi is a peaceful riverside town that becomes electrified every weekend — as gem traders from around the world gather for one of the most influential gemstone markets in the world.

For decades, it has been a backbone of Thailand’s colored gem industry, especially for:
– Rubies from Burma and Mozambique
– Sapphires from Sri Lanka, Madagascar, Cambodia
– Spinels, garnets, and zircon
– Geuda sapphires for heat treatment

What Happens in Chanthaburi?

Chanthaburi is where the middle stage of a gem’s life plays out:
1. Rough stones arrive from Sri Lanka, Madagascar, Mozambique, Cambodia, Tanzania, and beyond.
2. They are cut, polished, and calibrated in small family-run lapidaries.
3. Some undergo heat treatment to improve colour and clarity.
4. Polished stones are sorted, graded, and sold in parcel or piece to global buyers.

Many international jewellery brands — including high-end houses — source directly or indirectly from here.

The Chanthaburi Weekend Market

The town’s gem market is held every Friday to Sunday, concentrated in the Talad Ploy (Gemstone Market) area. It’s a dense, buzzing grid of:
– Narrow shophouses
– Traders seated behind glass-top counters
– Tiny parcels zipped open and examined under white lights
– Instant, whispered negotiations

You’ll find everything here: From calibrated 2 mm sapphires for watch dials to 6-carat heated Burmese rubies for high jewellery.

Gem Types Commonly Traded in Chanthaburi

Heat Treatment Capital of the World

Chanthaburi is known for its sophisticated gem heating industry, especially for Geuda sapphires and rubies. Treatments include:
– High-temperature heating to improve colour
– Flux-assisted healing for rubies
– Glass-filling in heavily fractured rubies (disclosed or undisclosed)
– Surface diffusion treatments (less common today)

While treated stones dominate, full disclosure is expected in professional transactions. Many labs in the region, such as GIT, AIGS, and BGL, issue local certificates.

Why Chanthaburi Remains Relevant

Despite sourcing shifts to Africa and Sri Lanka, Chanthaburi continues to thrive due to:
– Cutting-edge lapidary skills
– Efficient heat treatment networks
– Strong export relationships
– Global trust in its calibrated supply chains

It’s a preferred hub for buyers from:
China
USA
Japan
Korea
India
Europe

Chanthaburi vs Ratnapura vs Beruwala

At PreciousCarats: Why We Work With Chanthaburi

At PreciousCarats, we honour both origin and process.
When we choose heat-treated gems, they often pass through Chanthaburi’s expert hands.

– Our Geuda-origin sapphires are heated in Thailand, then re-certified.
– We partner only with cutters and treaters who uphold ethical practices.
– All treatments are disclosed with integrity.

Because a gem’s journey matters.
Not just where it’s from — but who brought it to life.

FAQs

Are all gems in Chanthaburi treated?
No. While heat treatment is common, untreated stones are available and often priced higher. Always check certification.

Can tourists buy safely in Chanthaburi?
Yes — but knowledge is key. Work with a local guide or trusted trader.

Why is Chanthaburi important if it doesn’t mine gems?
Because it adds maximum value to gems: cutting, heating, polishing, and grading. It’s the “refinery” of the gem world.

Conclusion: The Alchemist’s Town

Chanthaburi doesn’t just sell gems.
It transforms them.

From dull rough to radiant sparkle, from quiet parcels to international auctions — this town shapes the gems the world admires.

If Sri Lanka is the birthplace of many stones…
Chanthaburi is the place they become unforgettable.