Natural Zircon in Bangkok: Blue Cambodian Zircon and Every Colour Worth Buying
By Ansh Gupta, second generation at KC Gems House, Jewelry Trade Center, Silom Road, Bangkok
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Alt: Loose natural blue zircon gemstones from Cambodia sparkling on a white gem paper at the Jewelry Trade Center in Bangkok
Zircon has the worst name in the gem world. Say “zircon” to most people and they think of cubic zirconia, the cheap lab-made diamond imitation. That confusion is the best thing that ever happened to zircon buyers, because it keeps prices low for one of the most brilliant natural gemstones on earth.
Natural zircon is a real mineral, it is older than almost anything else on the planet, and a well-cut blue zircon has a fire and sparkle that comes close to diamond. Thailand and Cambodia have been the centre of the zircon trade for more than a century, and in Thailand it holds a place of honour as เพทาย, one of the nine sacred nopphakao stones.
My family has traded coloured stones in Bangkok since 1990, from our office inside the Jewelry Trade Center on Silom Road. This page explains everything I would tell you at my desk: what zircon is, why it is not cubic zirconia, how blue zircon gets its colour, what it costs per carat in 2026, and how to buy it safely in Bangkok. If you already know what you want, skip to how to buy zircon from us or see the full natural gemstones collection.
Zircon at a glance
Mineral — Zirconium silicate (ZrSiO4)
Hardness — 6 to 7.5 on the Mohs scale
Crystal system — Tetragonal, strongly doubly refractive
Refractive index — About 1.81 to 1.98, among the highest of any natural gem
Dispersion (fire) — About 0.039, close to diamond’s 0.044
Main colours — Blue, golden yellow, orange, red, brown, green, colourless
Key origins — Cambodia (Ratanakiri), Sri Lanka, Myanmar, Vietnam, Tanzania, Australia, Thailand (historic)
Typical treatment — Heat is standard for blue, colourless and many golden stones
Birthstone — December
Thai name — เพทาย
What zircon actually is
Zircon is a natural mineral, zirconium silicate. It forms in igneous and metamorphic rocks all over the world and is so tough chemically that it survives erosion for billions of years. Zircon crystals from the Jack Hills in Western Australia are about 4.4 billion years old, which makes them the oldest known pieces of the earth’s crust. Geologists use zircon to date rocks for exactly that reason.
Gem zircon is the transparent, well-coloured part of that story. Two properties make it special:
1. A very high refractive index. Zircon bends light more strongly than sapphire, spinel or almost any natural coloured gem. That gives it an adamantine, almost diamond-like lustre.
2. High dispersion. Zircon splits white light into rainbow flashes, called fire, nearly as strongly as diamond. A well-cut white or blue zircon throws colour across a room.
Because of that brilliance, colourless zircon was sold as a diamond substitute for centuries. Sri Lankan white zircon was known as “Matara diamond” after the town in southern Sri Lanka where much of it was found.
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zircon-fire-closeup.jpg
Alt: Close-up of a round blue zircon showing rainbow fire flashes similar to a diamond
Zircon vs cubic zirconia
This is the first thing every new zircon buyer should understand.
What it is · Natural zircon: A natural mineral, zirconium silicate · Cubic zirconia (CZ): A man-made material, zirconium oxide
Origin · Natural zircon: Mined from the earth · Cubic zirconia (CZ): Made in factories since the 1970s
Rarity · Natural zircon: Natural, especially rare in fine blue · Cubic zirconia (CZ): Unlimited supply
Double refraction · Natural zircon: Strong, you can see doubled facet edges · Cubic zirconia (CZ): None
Value · Natural zircon: Real gemstone value · Cubic zirconia (CZ): Very low
The only thing they share is the element zirconium. Cubic zirconia was named after zirconium, not after zircon. If anyone offers you “zircon” for a few dollars a carat in perfect, flawless large sizes, ask whether it is natural zircon or CZ, and get it in writing.
Zircon in Thai tradition
In Thailand, zircon is เพทาย (petai), one of the nine stones of the นพเก้า (nopphakao) set with diamond, ruby, emerald, yellow sapphire, garnet, blue sapphire, moonstone and cat’s eye. The nopphakao ring was a mark of rank at the Siamese court, and zircon’s place in it reflects how long Thai and Cambodian traders have handled this stone. Thai buyers often look for golden and yellow-brown zircon for nopphakao jewellery and blue zircon for modern designs.
A short history of zircon in this region
Zircon has been traded through Southeast Asia for centuries, but the modern blue zircon trade began around the early 20th century, when burners near the Thai and Cambodian border learned to turn brown Cambodian zircon blue. The stones became fashionable in Europe and America in the 1920s and 1930s, where they were sold as “starlite” and set in Art Deco jewellery alongside diamonds. Victorian and Art Deco jewellery from that period often contains blue and white zircon that came through Bangkok.
Thai gem fields in Chanthaburi and Trat also produced zircon from the same basalt-related deposits that gave Thailand its sapphires and rubies. Production there is small today, but the skills it built, especially in burning and cutting, are why Bangkok and Chanthaburi remain the world’s zircon trading centres.
Zircon colours and how to judge them
Blue zircon
Blue is the zircon most of the world knows, and for good reason. Fine blue zircon ranges from a light sky blue to an intense, slightly greenish “Ratanakiri blue” with high brilliance. The most valued colour is a vivid, pure to slightly greenish blue, medium in tone, with strong sparkle and no grey.
Almost all blue zircon starts life as reddish brown rough from Ratanakiri province in northeastern Cambodia. Thai and Cambodian burners discovered more than a century ago that heating this rough in a low-oxygen environment turns it a brilliant blue. This heating is the accepted, standard treatment for blue zircon worldwide. A natural, unheated blue zircon of good colour is extremely rare.
What lowers the price of blue zircon: a grey or dull cast, an inky dark tone, cloudiness, visible inclusions, and a cut that hides the stone’s brilliance.
Golden, yellow and orange zircon
Golden zircon ranges from champagne yellow to a rich honey and cognac orange. Some golden zircon is natural colour, and some is heated. Fine golden zircon has a warm, glowing colour and strong fire, and it is beautiful in yellow gold. Many Thai buyers choose golden zircon for nopphakao and lucky jewellery.
Red and brown zircon
Natural red zircon, from Tanzania, Sri Lanka and Cambodia, ranges from cinnamon red to a rich wine colour. Fine, clean red zircon is uncommon and well loved by collectors. Brown zircon is the most common natural colour and is usually the starting point for heat treatment.
Green zircon
Green zircon, mostly from Sri Lanka, ranges from yellow-green to olive. Some green zircon is “low” zircon, whose crystal structure has been damaged over geological time by natural trace radioactive elements. Low zircon is softer, less brilliant and has a soft, sleepy look. Stones sold in the gem trade are tested and are safe to wear, but this is one more reason to buy green zircon from a dealer who knows the material.
White (colourless) zircon
Colourless zircon, often produced by heating brown or yellow stones, is the historic diamond substitute. It has strong fire and brilliance and costs a small fraction of a diamond. It is a lovely choice for side stones and vintage-style designs.
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Alt: A row of natural zircon gemstones in blue, golden yellow, orange, red, green and colourless
Where the best zircon comes from
Cambodia (Ratanakiri) — The world’s main source of rough for blue zircon, plus golden and red
Sri Lanka — Yellow, green, brown, colourless and some blue; historic “Matara diamond”
Myanmar — Brown, yellow and blue-heating material
Vietnam — Brown rough used for blue and colourless after heating
Tanzania — Red, orange and golden zircon
Australia — Brown, yellow and pink zircon in the Northern Territory and Queensland
Thailand — Historic production from the basalt gem fields of Chanthaburi and Trat
Cambodian blue zircon is the benchmark. When a dealer says “Ratanakiri zircon” or “Cambodian blue zircon”, they mean the classic, vivid blue that has been heated from Cambodian brown rough. Most of it is cut in Thailand.
Is zircon treated?
Yes, often, and that is normal. Here is the honest breakdown.
• Blue zircon: Almost always heated. Heating brown Cambodian rough produces the blue. This is a stable, accepted treatment and is reflected in all market prices. Any reputable dealer will tell you blue zircon is heated.
• Colourless zircon: Usually heated from brown or yellow rough.
• Golden and orange zircon: Sometimes natural colour, sometimes heated.
• Red and green zircon: Usually natural colour.
A small number of heated blue zircons can lose some colour after long exposure to strong sunlight or UV, and occasionally partly revert toward brown. It is uncommon with good material, and the colour can usually be restored by a further gentle heating. We tell every buyer about it, and it is one reason we prefer stable, well-tested stones from trusted burners.
Our rule is the same for every stone: the treatment goes on your invoice in writing before you pay. For blue zircon, that means “natural zircon, heated”. If you want a laboratory report, GIT and AIGS are a short walk from our desk at JTC.
Clarity, cut and carat weight in zircon
Clarity
Blue and golden zircon are expected to be eye clean, and clean stones are easy to find in sizes up to ten carats and more. Because zircon is so brilliant, even small inclusions can show, so we check stones face up under daylight and with a loupe.
Double refraction and cut
Zircon is strongly doubly refractive. Look through the table of a zircon with a loupe and you will see the back facet edges doubled. This is a key identification feature, and it also affects cutting. Good cutters orient the stone so the doubling does not make it look fuzzy face up.
Classic zircon cuts are round brilliants and the “zircon cut”, a round brilliant with an extra row of facets around the culet that maximises fire. Ovals, cushions and emerald cuts are also popular.
Brittleness
Zircon is brittle. Its facet edges can chip when stones rub against each other in a parcel or a jewellery box, an effect the trade calls “paper wear”. This does not make zircon a bad jewellery stone, it just means you should protect the edges with good settings and store zircon on its own.
Carat weight
Zircon is dense, so it weighs more for its size than diamond, sapphire or spinel. A one carat zircon looks smaller than a one carat diamond. Clean blue zircon is available in large sizes, and prices per carat rise steadily rather than jumping, which makes big zircons excellent value.
Zircon size guide
Approximate weights for well-cut round blue zircon. Ovals and cushions are similar for the same face-up area.
5 — 0.75
6 — 1.3
7 — 2.0
8 — 3.0
9 — 4.3
10 — 6.0
12 — 10.0
Zircon price per carat in 2026
These are typical Bangkok retail ranges for natural, faceted, eye-clean zircon from 1 to 5 carats with a good cut. Larger sizes and exceptional colour cost more.
Colourless (white) zircon — $20 to $80
Brown and champagne zircon — $15 to $60
Golden and honey zircon — $30 to $150
Green zircon — $40 to $250
Red zircon, fine — $100 to $500
Blue zircon, light to medium — $50 to $150
Blue zircon, vivid Ratanakiri, 5 ct and over — $150 to $500
What moves the price:
1. Colour intensity. A vivid, saturated blue costs several times a pale one.
2. Brilliance. A sparkling, well-cut stone sells at a premium over a dull one of the same colour.
3. Size. Zircon prices climb gradually with size, so large stones are good value.
4. Clarity. Eye-clean is the standard. Visible inclusions cut the price sharply.
For context, a fine five carat blue zircon often costs less than a commercial one carat blue sapphire.
Zircon vs other blue stones
Stone: Blue zircon · Hardness: 6 to 7.5 · Colour: Vivid sky to teal blue · Brilliance: Very high, strong fire · Price for a fine 3 ct: Low
Stone: Blue topaz · Hardness: 8 · Colour: Sky, Swiss and London blue (irradiated) · Brilliance: Good · Price for a fine 3 ct: Very low
Stone: Aquamarine · Hardness: 7.5 to 8 · Colour: Light sea blue · Brilliance: Good · Price for a fine 3 ct: Moderate
Stone: Blue spinel · Hardness: 8 · Colour: Grey-blue to cobalt · Brilliance: High · Price for a fine 3 ct: Moderate to very high
Stone: Blue sapphire · Hardness: 9 · Colour: Cornflower to royal blue · Brilliance: Good · Price for a fine 3 ct: High
If you want the most sparkle for the money in a blue stone, zircon wins. If you want the most durable blue stone for daily wear, sapphire wins. You can see how sapphire prices change with treatment and size on our natural vs lab sapphire price calculator.
What your budget buys in zircon
Roughly what a budget gets you in Bangkok for a loose natural zircon, before setting.
• Under $100: A bright one to two carat golden or white zircon, or a light blue zircon of about one carat. A lovely first gemstone or gift.
• $100 to $500: A two to four carat blue zircon with good colour and brilliance, or a fine golden zircon of three to five carats.
• $500 to $2,000: A vivid Ratanakiri blue zircon of four to eight carats, a fine red zircon of two to three carats, or a matched pair of blue zircons for earrings.
• Over $2,000: A collector blue zircon of ten carats or more with top colour and cut, or an exceptional red or golden stone with a laboratory report.
Setting costs come on top. A 14k or 18k gold setting made in Bangkok usually costs much less than in Europe or the US, because you are buying at factory level.
Common zircon buying mistakes
1. Buying CZ by mistake. Very cheap, perfectly flawless “zircon” in large sizes is often cubic zirconia. Ask for “natural zircon” in writing.
2. Choosing the darkest blue. With zircon, a vivid medium blue usually sparkles more than an inky dark one. Brilliance matters as much as colour.
3. Ignoring chipped edges. Old parcel stones often have paper wear on the facet junctions. A recut or polish can fix it, but price it in.
4. Picking a fragile setting for a daily ring. Thin claws on a large zircon invite chips. Ask for a protective setting.
5. Leaving it in the sun. Heated blue zircon should not live on a sunny windowsill or dashboard.
How to buy zircon safely in Bangkok
1. Make sure it is natural zircon, not CZ. Ask the dealer to write “natural zircon” on the invoice. A loupe will show doubled facet edges in real zircon.
2. Ask about heat. For blue zircon, “heated” is normal and should be stated.
3. Look in daylight. Zircon’s blue can shift slightly between daylight and indoor light. Choose a stone you like in both.
4. Check the edges. Look for chips on the facet junctions. Good stones have crisp, unchipped edges.
5. Buy from an established dealer. Avoid any shop a stranger or tuk-tuk driver takes you to, and never buy gems “to resell at home”.
6. Get a report for important stones. For stones over five carats, a GIT or AIGS identification report gives you peace of mind.
For a full guide, read why Bangkok is one of the world’s best places to buy gemstones and our how to buy page.
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Alt: View through a loupe of a zircon showing doubled back facet edges caused by strong double refraction
From Ratanakiri to Bangkok: how blue zircon reaches JTC
The blue zircon story is one of the oldest gem trades in this region.
1. Mining. Zircon is dug from gravels in Ratanakiri province, Cambodia, mostly by small-scale miners working by hand.
2. Burning. The reddish brown rough is heated by specialist burners, traditionally in Cambodia and Thailand. The burner’s skill decides how vivid and how stable the blue will be.
3. Cutting. Thai cutters, many in Chanthaburi and Bangkok, cut the stones into brilliants, ovals and cushions to bring out the fire.
4. Trading in Silom. Finished stones reach the dealer offices of JTC and the streets around Silom and Mahesak Road, where buyers from around the world source them.
Buying in Silom puts you close to the end of that chain, without the retail markups that a jeweller abroad has to add.
Why buy zircon from us
There are many honest zircon dealers in Bangkok. Here is how we work.
• Family trade since 1990. KC Gems House was built by my father, KC Gupta, who began trading coloured stones in Bangkok in 1990. I am the second generation. Read more on our family business page and my page.
• Inside JTC, at trade level. Our office is in the Jewelry Trade Center on Silom Road, where the trade buys.
• Stable colour, tested stones. We work with suppliers whose blue zircon colour we know is stable, and we tell you how each stone has been treated.
• Natural, in writing. Every zircon is invoiced as natural zircon with its treatment stated. No CZ, no confusion.
• Reports on request. GIT and AIGS are a short walk away; AIGS is in the same building.
• Set here, safely. We set zircon in 10k, 14k and 18k gold with protective settings that guard the facet edges. See custom jewellery in Bangkok or start a custom order.
• Worldwide shipping. Daylight videos and photos before you pay, and insured shipping to the UK, Europe, the US and the Middle East.
Zircon jewellery ideas
• Blue zircon cocktail rings. A five to ten carat blue zircon in white gold or platinum is one of the most spectacular rings you can buy for the money.
• Halo and three-stone rings. Zircon’s fire pairs beautifully with small diamonds or white zircon side stones.
• Earrings and pendants. Earrings are the safest place for zircon, since they take little wear. Matched blue pairs are easy to source.
• Nopphakao rings. Zircon is one of the nine nopphakao stones. We make nopphakao rings with natural stones on request.
• December birthstone gifts. Blue zircon is a December birthstone and makes a meaningful family gift.
• Vintage-style rings. White zircon was a favourite of Art Deco jewellers. It suits milgrain and vintage designs like our Art Deco milgrain ring.
Read our breakdown of what factory-price custom jewellery at JTC costs to plan your budget.
Caring for zircon
• Protect the edges. Store zircon in its own pouch or compartment, away from other stones.
• Choose protective settings for rings. Bezel, halo or deeper prongs help prevent chipping.
• Avoid prolonged strong sunlight and UV for heated blue zircon, such as leaving it on a sunny windowsill.
• Clean gently. Warm water, mild soap and a soft brush. Avoid ultrasonic and steam cleaners.
• Avoid sudden heat during jewellery repairs. Tell your jeweller the stone is zircon.
Zircon for wholesale buyers
We supply calibrated blue, golden and white zircon in standard sizes, matched pairs and layouts, plus single large stones. Tell us the colour, sizes, quantity and budget and we will prepare a parcel with videos. See our wholesale page.
Common zircon myths
“Zircon is fake.” No. It is a natural mineral. Cubic zirconia is the fake.
“Zircon is radioactive.” Gem zircon used in jewellery is safe to wear. Some green “low” zircon from Sri Lanka contains trace natural radioactive elements, and the gem trade tests this material. Blue, golden and white zircon sold in Bangkok are standard, safe jewellery stones.
“Heated zircon is low quality.” Heating is the standard way blue zircon is produced worldwide. What matters is the final colour, its stability, and honest disclosure.
“Zircon is too soft for jewellery.” Zircon is 6 to 7.5 on the Mohs scale, similar to tanzanite and peridot. It is fine in earrings, pendants and well-set rings with a little care.
เพทายแท้ ที่ JTC สีลม
เพทาย (Zircon) เป็นพลอยธรรมชาติ และเป็นหนึ่งในพลอยนพเก้าทั้งเก้าชนิด ไม่ใช่เพชรรัสเซียหรือคิวบิกเซอร์โคเนีย (CZ) ซึ่งเป็นวัสดุสังเคราะห์ เพทายมีประกายไฟสูงใกล้เคียงเพชร และมีหลายสี ทั้งสีฟ้า สีเหลืองทอง สีส้ม สีแดง สีเขียว และสีขาว
เพทายสีฟ้าส่วนใหญ่มาจากจังหวัดรัตนคีรี ประเทศกัมพูชา และผ่านการเผาเพื่อให้ได้สีฟ้าสดใส ซึ่งเป็นวิธีมาตรฐานของตลาดโลก เราแจ้งการเผาให้ทราบเป็นลายลักษณ์อักษรทุกครั้ง
เราคือ KC Gems House ค้าพลอยในกรุงเทพฯ มาตั้งแต่ปี 1990 สำนักงานอยู่ในอาคาร Jewelry Trade Center ถนนสีลม เรามีเพทายสีฟ้า สีเหลืองทอง และสีขาว พร้อมส่งตรวจใบรับรองจาก GIT หรือ AIGS และรับทำแหวนเพทาย แหวนนพเก้า จี้ และต่างหู ด้วยทอง 10K 14K และ 18K
ราคาเพทายขึ้นอยู่กับสี ความสด ประกายไฟ และขนาด เพทายสีฟ้าสดขนาดใหญ่มีราคาสูงกว่าสีอ่อนหรือสีขาวหลายเท่า ติดต่อเราเพื่อดูพลอยจริงและราคาปัจจุบัน
Frequently asked questions about zircon
Is zircon a real gemstone?
Yes. Zircon is a natural mineral, zirconium silicate, mined in Cambodia, Sri Lanka, Myanmar, Tanzania, Australia and elsewhere. It is not the same as cubic zirconia, which is a man-made diamond imitation.
What is the difference between zircon and cubic zirconia?
Zircon is a natural gemstone made of zirconium silicate. Cubic zirconia is a synthetic material made of zirconium oxide, first mass-produced in the 1970s. They only share the element zirconium. Natural zircon shows strong double refraction; cubic zirconia does not.
Is blue zircon natural?
Blue zircon is natural zircon, but its blue colour is almost always produced by heating reddish brown rough from Cambodia. Heating is the standard, accepted treatment and should always be disclosed.
How much does blue zircon cost per carat?
For eye-clean stones from 1 to 5 carats, light to medium blue zircon runs about $50 to $150 per carat in Bangkok, and vivid Ratanakiri blue in larger sizes about $150 to $500 per carat.
Where is the best place to buy zircon in Bangkok?
At established dealers in and around the Jewelry Trade Center (JTC) on Silom Road. Ask for “natural zircon” and the treatment in writing, check for chipped edges, and avoid any shop a stranger takes you to. Our office is inside JTC.
Does blue zircon fade?
Most stable blue zircon keeps its colour. A small number of heated stones can lose some colour after long exposure to strong sunlight or UV. Avoid leaving zircon in direct sun for long periods, and buy from a dealer who knows the burner.
Is zircon good for an engagement ring?
It can be, with a protective setting and some care. Zircon is 6 to 7.5 on the Mohs scale and brittle at the edges, so a bezel or halo setting is best. For a ring worn every day for decades, sapphire or spinel are more durable.
What is zircon in Thai?
Zircon is เพทาย in Thai. It is one of the nine nopphakao stones in the traditional Thai nine-gem ring.
Why does my zircon look fuzzy under a loupe?
That is double refraction. Zircon splits light into two rays, so you see the back facet edges doubled. It is a sign that the stone is natural zircon rather than cubic zirconia or glass.
Do you ship zircon internationally?
Yes. We send daylight videos and photos before payment and ship insured worldwide.
Talk to us about zircon
Tell us the colour, size and budget you have in mind, and we will send real daylight videos with the treatment confirmed. Visit us at JTC, or buy remotely.
Ask about a zircon
Explore other natural stones: spinel, garnet, star sapphire, pink and padparadscha sapphire, tourmaline, amethyst and citrine and cat’s eye chrysoberyl. Or go back to all natural gemstones.