Zircon Buying Guide: Natural Zircon vs Cubic Zirconia
How to tell it from CZ, why almost every blue zircon was heated, where it can be worn, and what sellers ask per carat, from someone who selects stones one at a time.
Natural zircon is a real gemstone, mined from the ground; cubic zirconia is made in a factory. Before you choose one, check three things: back facets that look doubled under a loupe, the heat that made almost every blue zircon, and facet edges free of chips. Then wear it where it takes few knocks.
We have no zircon right now; among the stones that can stand in for it, our blue spinels are below.
- Natural or not?
- A natural gem; cubic zirconia is manmade
- How to tell
- Doubled back facets under a loupe
- Treatment
- Blue and colourless: almost always heated
- Hardness
- 6 to 7.5 on the Mohs scale
- Best worn as
- Earrings, pendant, protected ring
Is zircon the same as cubic zirconia?
No. Zircon is a natural gem. Cubic zirconia, or CZ, is a manmade diamond imitation, on the market since the 1970s and now the most common of them all. The names sound alike, and colourless zircon was itself widely used as a diamond substitute. So for many people, the word zircon still means imitation.
It is the reverse: one zircon crystal from Australia has been dated to 4.4 billion years, older than any rock found on the surface of the Earth.
| Natural zircon | Cubic zirconia | |
|---|---|---|
| Origin | Mined | Made in a factory |
| Under a loupe | Back facet edges look doubled | No doubling |
| Fire | Moderate | Strong |
| Hardness | 6 to 7.5 | 8 to 8.5 |
| Weight for its size | High | Higher still |
The doubling is the test you can do yourself. Zircon splits light in two so strongly that, through a loupe, the edges of the back facets show twice, and in larger stones you can sometimes see it with the naked eye. Look through the side facets rather than straight down the table, where a zircon can hide it, and check in three directions. CZ never doubles.
Under a loupe
Doubled or single: the back edges
Look into the stone through a side facet, at the edges where the back facets meet. Zircon shows each one twice. Cubic zirconia shows it once.
- Doubled back edges Each edge at the back shows twice, side by side. In a large stone, sometimes to the naked eye.
- Through the side, in three directions Straight down the table a zircon can hide it. Look through the side facets and turn the stone.
- Single, sharp edges Each edge shows once: cubic zirconia does not split light in two.
Illustration. Simplified drawings of what to look for, not photographs of real stones.
Doubling points to zircon; it is not proof on its own. A drawing does not replace a laboratory.
Which zircon colour is worth the most?
Blue, by demand. Dealers report that at least 80 percent of zircons sold are blue, and blue usually commands higher prices than any other colour. It runs from very slightly greenish blue to strongly greenish blue, and that greenish tint is the signature of the stone.
Zircon also comes in yellow, orange, red, brown, green and, rarely, purple. Red and green ones are sought by collectors. Colours are often light and muted; the finest stones have strong, rich colour. Many untreated zircons look slightly cloudy or smoky. A little is normal; a lot is a reason to pass.
Size depends on colour: blue and green usually from 1 to 10 carats, yellow and orange up to about 5, red and purple smaller. A colourless zircon belongs with the white stones, which our white gemstones guide compares side by side.
Is blue zircon natural or heated?
Natural, and heated. In nature, most zircons are yellowish or reddish brown. Heated in charcoal to about 875°C, some turn blue, others colourless; a later heating, in air, gives colourless, yellow, orange or red. Virtually all blue and colourless zircons on the market have been through it, and the heat cannot be detected, so the trade assumes it.
The colour is usually stable. But some heated stones drift back towards their original light brown when exposed to light, and heat can make zircon more brittle. A seller should tell you all of this. As I see it, heat is fine; silence about it is not. Get the treatment in writing.
Can you wear zircon every day?
Yes, with a setting that protects it. Zircon rates 6 to 7.5 on the Mohs scale and its toughness is only fair to good. It can be brittle, and careless handling wears down crisp facet edges. Earrings and pendants are the safest places for it. In a ring, choose a setting that guards the edges, like a bezel.
Zircon next to stones you know
Hardness is resistance to scratches. Toughness is resistance to chips and breaks. A ring needs both. Zircon is selected: tap another stone to compare.
Touch a point to read about the stone.
Zircon Mohs 6 to 7.5 · Toughness: Fair to good
6 to 7.5 on the Mohs scale, fair to good toughness. Heat-treated stones can be brittle and facet edges wear: earrings, a pendant, or a ring setting that guards the edges.
Tanzanite Mohs 6 to 7 · Toughness: Fair to poor
6 to 7 on the Mohs scale, fair to poor toughness. Best in earrings or a pendant; in a ring it needs care.
Turquoise Mohs 5 to 6 · Toughness: Generally fair to good
5 to 6 on the Mohs scale. Earrings or a pendant.
Topaz Mohs 8 · Toughness: Poor, because of cleavage
8 on the Mohs scale, but a knock in the wrong place can split it along its cleavage. In a ring, a protective setting.
Spinel Mohs 8 · Toughness: Good
8 on the Mohs scale with good toughness: a very good ring stone.
Sapphire Mohs 9 · Toughness: Usually excellent
9 on the Mohs scale and usually excellent toughness: an excellent ring stone.
Diamond Mohs 10 · Toughness: Good in its cleavage directions, exceptional in all others
10 on the Mohs scale, harder than any other gem. A hard knock at the wrong angle can still chip it.
| Stone | Mohs | Toughness |
|---|---|---|
| 1Zircon6 to 7.5 on the Mohs scale, fair to good toughness. Heat-treated stones can be brittle and facet edges wear: earrings, a pendant, or a ring setting that guards the edges. | 6 to 7.5 | Fair to good |
| 2Tanzanite6 to 7 on the Mohs scale, fair to poor toughness. Best in earrings or a pendant; in a ring it needs care. | 6 to 7 | Fair to poor |
| 3Turquoise5 to 6 on the Mohs scale. Earrings or a pendant. | 5 to 6 | Generally fair to good |
| 4Topaz8 on the Mohs scale, but a knock in the wrong place can split it along its cleavage. In a ring, a protective setting. | 8 | Poor, because of cleavage |
| 5Spinel8 on the Mohs scale with good toughness: a very good ring stone. | 8 | Good |
| 6Sapphire9 on the Mohs scale and usually excellent toughness: an excellent ring stone. | 9 | Usually excellent |
| 7Diamond10 on the Mohs scale, harder than any other gem. A hard knock at the wrong angle can still chip it. | 10 | Good in its cleavage directions, exceptional in all others |
Points that would overlap are moved apart a little. The exact values are in the table.
Toughness has no number: it is rated in words, and one stone can sit on two lines. Inclusions, fractures or some treatments lower it for any single stone.
Look at the edges before you choose: chipped or worn facet edges are the known weakness of zircon, so ask for crisp ones. Store it in its own pouch, away from harder stones. Warm, soapy water is safe; ultrasonic and steam cleaners are risky. And tell the jeweller it is zircon before any repair: high heat can alter its colour.
Is zircon expensive?
Usually not. Zircon is plentiful in South East Asia and Madagascar, and prospectors often find it while looking for sapphire. For blue zircon of half a carat to 3 carats, the four sellers we read from 7 to 9 October 2026 had median asking prices of $50 to $424 a carat, across 94 listings.
Colourless zircon is cheaper: 30 of 34 listings from 10 shops on one marketplace asked $60 a carat or less on 7 October 2026. Asking prices, not sale prices.
How that compares with the other birthstones: our birthstones ranked by price. And for the wider market, our coloured gemstone market statistics.
What should you ask before choosing a zircon?
Five questions before you choose a zircon
Tick them as you get answers. The button copies all five, ready to send.
5 points
A message ready to send to the seller, with all the questions.
See the message
Hello, I am interested in this zircon. Before I decide, could you answer a few questions in writing? 1. Is this stone natural zircon, and not cubic zirconia? Could you write “natural zircon” on the listing or the invoice? 2. Has the stone been heated, or treated in any other way? Could you state it in writing? 3. Could you send photos or a short video of the stone in daylight? 4. Are the facet edges crisp, with no chips or wear? Could you show them up close? 5. Does the stone come with a report from an independent laboratory? If not, can one be done before I decide? Thank you for your time.
What a report proves, and what it does not: our guide to gemstone certificates.
Quick answers
Is zircon a real gemstone?
Is zircon a diamond?
Why is zircon so cheap?
Is zircon good for an engagement ring?
Is zircon a birthstone?
Choose the fire, then protect it
Zircon is a real stone with a borrowed reputation. Look for the doubling, ask about the heat, check the edges, and give it a setting that guards them. If you have a zircon in mind, describe it and we will look for it.
