The fastest way to tell moissanite from diamond is a combined diamond and moissanite tester, which a jeweler can run in a few seconds, usually at no charge. At home, a 10x loupe often shows the giveaway: moissanite is doubly refractive, so when you look through the stone at an angle the back facet edges appear doubled, while a diamond's edges look single and sharp. Moissanite also throws strong rainbow flashes, about twice the fire of diamond. As for value, moissanite is a lab made stone that has become very inexpensive. As of late 2026, a loose 1 carat moissanite with a GRA card sells for roughly $20-100 online, branded stones from the original maker cost more at retail, and on the resale market the stone itself brings very little. A moissanite ring is usually worth about the value of its metal.
Two questions often get mixed together. The first is whether a stone sold to you as a diamond is actually moissanite. The second is whether a stone sold as moissanite is really moissanite and not cubic zirconia or glass. The tests below answer both, and the paperwork that comes with moissanite answers neither.
Quick answer
- A jeweler's combined diamond and moissanite tester separates them in seconds. A basic thermal diamond tester alone reads moissanite as diamond.
- Under a 10x loupe, doubled facet edges seen at an angle mean moissanite. Diamond shows single edges.
- Loose moissanite: roughly $20-100 for 1 carat online with a GRA card, more for branded stones at retail. Resale of the stone: usually $0-50.
- A moissanite ring is mostly valued for its metal: a 3 gram 14k ring contains about $225 of gold at $4,000 gold.
How to tell if moissanite is real, step by step
- Read the ring before the stone. Look inside the band for metal marks such as 14K, 585, 18K, 750, 925 or PT950. Many moissanite rings are sold in 925 sterling silver or 10k and 14k gold. A stone sold as a large diamond in a sterling silver mount is a strong hint that it is not a diamond.
- Look for a girdle inscription. Many moissanite stones sold with GRA paperwork have a tiny laser inscription on the girdle, the thin edge around the widest part of the stone, often beginning with GRA followed by a number. Natural and lab-grown diamonds with GIA or IGI reports also carry inscriptions, but with those labs' report numbers.
- Use a loupe and look for doubling. Moissanite is doubly refractive. Look through the side of the stone or through the crown at an angle toward the back facets. In moissanite the facet junctions look doubled, like a slightly blurred double line. Cutters often orient the stone to hide this through the top, so tilt it. Diamond and cubic zirconia are singly refractive and show crisp single edges.
- Watch the fire. Moissanite has a dispersion of about 0.104, more than twice diamond's 0.044. In sunlight it throws strong rainbow flashes from every facet, sometimes described as a disco ball effect. A diamond shows more white sparkle with flashes of color. This is a clue, not proof.
- Check the color. Older moissanite, made before about 2015, often has a faint yellow or green tint, especially in larger stones. Modern colorless moissanite is close to diamond white, so color alone no longer settles it.
- Try a fog or water test only to rule out glass. Moissanite and diamond both disperse heat quickly and clear fog in a second or two. Glass and cubic zirconia stay fogged longer. These tests cannot separate moissanite from diamond.
- Use the right tester. A thermal diamond tester, the common pen style, reads moissanite as diamond because both conduct heat well. A combined tester adds an electrical conductivity test: moissanite conducts electricity, most diamonds do not. Rare blue boron bearing diamonds and some lab-grown diamonds can also conduct, which is why a borderline result goes to a gemologist.
- For proof, a gemologist or a lab. A gemologist with a refractometer, a polariscope and a microscope can confirm moissanite in minutes, and GIA or IGI can issue a report if a stone is truly in doubt.
Moissanite vs diamond vs common simulants
| Property | Moissanite | Diamond | Cubic zirconia | Glass |
|---|---|---|---|---|
| Hardness (Mohs) | 9.25 | 10 | 8 to 8.5 | 5 to 6 |
| Refraction | Double | Single | Single | Single |
| Fire (dispersion) | Very high, 0.104 | 0.044 | 0.060 | Low |
| Thermal tester | Reads as diamond | Diamond | Not diamond | Not diamond |
| Electrical conductivity | Conducts | Usually does not | Does not | Does not |
| Weight for same size | About 10 percent lighter than diamond | Baseline | About 70 percent heavier | Varies |
| Fog test | Clears fast | Clears fast | Stays fogged | Stays fogged |
| Facet edges with wear | Sharp | Sharp | Rounded with age | Rounded and chipped |
What moissanite is worth
Values are as of late 2026 and depend heavily on whether the stone is branded and what it is set in.
| Item | New, retail or online | Resale, used |
|---|---|---|
| Loose moissanite, 1 carat, generic with GRA card | $20-100 | $0-30 |
| Loose moissanite, 1 carat, branded (Charles & Colvard) | Roughly $300-600 | $20-100 |
| Moissanite ring in 925 sterling silver | $40-200 | $10-50 |
| Moissanite ring in 10k or 14k gold, 2 to 4 grams | $300-1,500 | Metal value, about $100-300 |
| Moissanite ring in 18k gold or platinum | $800-3,000 | Metal value plus a little |
| Older yellowish moissanite from before 2015 | Not sold new | $0-30 |
Sources agree that there is no real secondhand market for moissanite stones. Pawn shops and gold buyers pay for the metal and nothing for the stone. Online, loose moissanite with GRA paperwork is listed from about $35 per carat at wholesale and $40-250 at retail, and auction lots of 1 carat stones open at the equivalent of $20-25. Gold content is easy to work out: 14k gold is 58.3 percent pure, so at $4,000 an ounce it holds about $75 of gold per gram, and a refiner pays 70-90 percent of that. Our guide to old gold jewelry explains how to read the metal marks.
What GRA paperwork does and does not mean
Most moissanite sold today comes with a small plastic card or paper from GRA, which describes the stone as D color, VVS1 clarity and gives a report number you can look up online. GRA is not an independent gemological laboratory like GIA or IGI. Cards are supplied to sellers with report numbers already assigned, and an online match confirms the card, not the stone. The grades on the card are not comparable to diamond grades from a recognized lab. GRA paperwork is fine as a description of a moissanite purchase, but it is also used by people selling moissanite as diamond, and it is worth nothing as proof that a stone is a diamond. If a seller offers a GRA card for a diamond, treat it as moissanite until tested.
Common mistakes
- Trusting a pen style diamond tester alone. It reads moissanite as diamond. Make sure the tester checks for moissanite too.
- Treating GRA paperwork as a lab report. It is a seller supplied card and does not prove anything about a diamond.
- Assuming very strong rainbow fire means a better diamond. Unusually strong fire is one of the signs of moissanite.
- Expecting to resell moissanite near the purchase price. The resale value of the stone is close to zero. The metal holds the value.
- Calling moissanite fake. Moissanite is a real gemstone, silicon carbide, made in a lab. It is a fake only when it is sold as diamond.
- Overpaying for "lab diamond" that is moissanite. Lab-grown diamond and moissanite are different materials. Ask for a GIA or IGI report for a lab-grown diamond.
How WorthPic reads moissanite and diamond photos
WorthPic runs on the newest and most capable AI model available, tuned for exactly this kind of identification. From a sharp, close photo of the stone it looks at the fire pattern, the facet arrangement, the color and, in a good macro shot taken at an angle, any doubling of back facet edges. From the band it reads metal marks such as 14K, 585, 925 or PT950 and any maker's mark, and it reads girdle inscriptions or paperwork visible in the photos. It then says whether the stone most likely is moissanite, diamond or a simulant, and gives an honest value range for the piece, usually led by the metal. What it cannot do from a photo is measure electrical or thermal conductivity, refractive index or weight, and so it cannot prove what a stone is. It says so plainly and recommends a tester. It identifies and estimates. It does not authenticate, grade or appraise for insurance.
What to photograph
- The stone face up, sharp and close, in daylight.
- The stone from the side at an angle, as close as your camera allows, to show facet edges.
- The inside of the band, with metal marks readable.
- The girdle, if you can see an inscription with a loupe.
- Any paperwork, card or receipt, front and back.
- The whole piece in one photo for context.
When to get it looked at in person
If a stone matters to you, a jeweler with a combined diamond and moissanite tester gives a fast answer, and most will do it without a fee. Go to a gemologist if the tester gives a conductive reading on a stone sold as a diamond, if the stone is large, or if money is about to change hands. GIA and IGI issue reports for diamonds and can identify moissanite when it is submitted. For diamonds in general, see our guide on how to tell if a diamond is real, and for the metal, see how to tell if gold is real and what 925 means on jewelry.