Cambodia has a long history of gemstone mining, but buying gemstones in Siem Reap is one of the easiest ways for tourists to get scammed. I learned this the hard way.

I bought what I believed was a pink gemstone, sold with a confident story about rare Cambodian origins. Only after researching Cambodia’s real gem regions did I realise the story made no sense — and the stone itself was not what it claimed to be.

This article explains:
• Where real Cambodian gemstones actually come from
• Why Siem Reap market stones are usually fake or heavily treated
• What lead-glass filled stones are
• What visual signs to look for
• Where you should buy gemstones instead

If you are serious about gemstones, this is what you need to know before buying anything in Cambodia.

Contents show

1. Understanding Cambodia’s Real Gem Regions

Knowing Cambodia’s geography already protects you from many scams.

Pailin (Western Cambodia)

Pailin was historically famous for rubies and red corundum. However:
• Most mines are exhausted
• True Pailin rubies are now extremely rare
• They do not appear casually in tourist markets

If a vendor tells you:
“This pink stone is from Pailin”
that is already suspicious. Pailin produced deep red stones, not bright pink tourist gems.

Ratanakiri (Northeast Cambodia)

Ratanakiri is known for:
• Blue sapphires
• Blue zircon
• Greenish and teal stones

It is not known for:
• Pink sapphires
• Rubies

So when a seller claims:
“This pink stone is from Ratanakiri,”
they are contradicting Cambodia’s actual gem geology.

If the origin story does not match the region, the stone is almost certainly not what they say it is.

2. What Is Really Being Sold in Siem Reap Markets

Most “rubies” and “pink sapphires” in Siem Reap markets are not rare stones. They are usually:

Lead-Glass Filled Corundum

These stones begin as:
• Natural corundum
• Opaque
• Heavily fractured
• Low value

They are then:
• Heated
• Injected with molten lead glass
• Made transparent
• Intensely coloured
• Visually attractive

However:
• Their value collapses
• Their durability is reduced
• Their resale value is almost zero
• They crack easily
• They cannot handle heat from jewellery repair

Wholesale price:
Approximately $5–10 per carat

Tourist selling price:
$200–1000 or more per stone

This is not normal markup. It is selling an industrially altered stone as if it were a rare natural gem.

3. Plastic, Glass and Treated Stones: What’s the Difference?

In Siem Reap, you will encounter three main types of “fake” stones:

Plastic

• Very light
• Warms quickly in your hand
• Scratches easily
• No natural crystal structure

These are the cheapest and easiest to detect.

Lead-Glass Filled Stones

• Heavy
• Very shiny
• Often too perfect
• Show bubbles inside
• Show blue or orange flashes
• Have spiderweb-like cracks
• Colour pools in fractures

These are the most common and the most deceptive.

Heat-Treated Natural Stones

Heat treatment is common in the gem trade and can be legitimate — but only when:
• It is disclosed
• It is priced accordingly
• It comes with certification

In markets, treatment is almost never disclosed honestly.

4. Why Siem Reap Is the Worst Place to Buy Gems

Siem Reap is:
• A tourist city
• A souvenir hub
• Far from mining regions
• Far from gem laboratories
• Not a trading centre

What it is not:
• A gemstone exchange
• A gemological centre
• A professional dealer network

Most stones sold there come from:
• Thailand
• China
• Industrial treatment factories

They are then given Cambodian “origin stories” because Cambodia sounds exotic and authentic to tourists.

5. Visual Warning Signs to Look For

If you are shown a ruby or sapphire, look for:

• Blue flashes inside cracks
• Orange flashes inside fractures
• Bubbles
• Spiderweb patterns
• Colour pooling
• A glassy surface
• A stone that looks too clean and bright

These are classic signs of lead-glass filling.

Real stones:
• Have inclusions
• Have uneven colour
• Are rarely perfectly clear
• Are smaller
• Cost much more

If it looks too good for the price, it is not rare — it is treated.

6. The Certificate Trick

Many vendors will show:
• Laminated cards
• Homemade “certificates”
• Fake gemology reports

Only trust certificates from recognised labs such as:
• GIA
• GRS
• AIGS
• GIT

If a seller says:
“No need certificate, natural stone,”
that is a major red flag.

No lab report means:
Souvenir, not investment.

7. Where You Should Buy Instead

If you want Cambodian gemstones, buy them in:

• Phnom Penh from established dealers
• Bangkok’s gem district
• Chanthaburi (Thailand)
• From certified online sellers
• Only with lab reports
• Only with return policies
• Only loose stones (not pre-set jewellery)

Never buy gemstones from:
• Night markets
• Souvenir shops
• Tuk-tuk referrals
• “My family mine” stories

Stories are free. Gemstones are not.

8. The Psychology of the Scam

Market sellers do not sell stones.
They sell:
• Rarity
• Urgency
• National pride
• Romantic mining stories
• The thrill of discovery

They make you feel:
“I found something rare.”

Instead of:
“I verified something real.”

Gem buying is not emotional.
It is scientific and documented.

9. What You Should Buy in Siem Reap Instead

Siem Reap is fantastic for:
• Silver jewellery
• Handicrafts
• Pepper
• Scarves
• Textiles
• Wood carvings

But not for gemstones.

Cambodia does have real gems —
just not in tourist markets.

Final Rule

If you are in Siem Reap:
Do not buy gemstones from markets.

Not because Cambodia has no gems,
but because Siem Reap is not where they are traded professionally.

If it has:
No certificate
No mine record
No treatment disclosure
No return policy

Then it has:
No real value.

Quick Buyer Checklist

Before buying any gemstone:

✔ Exact mine location
✔ Treatment disclosed
✔ Recognised lab certificate
✔ Realistic price
✔ Return option
✔ Buy loose stone

If any of these are missing:
Walk away.