Simulated diamonds – or diamond simulants – may look like diamonds, but they do not have the same chemical, physical and optical properties. If you’re shopping for a diamond imitation, be sure you know what you’re getting and what you’re not.

Any gem can be imitated – gemologists call these imitations “simulants” – by laboratory-grown materials or by natural materials that closely resemble a particular gem. In the case of diamonds, various materials have been used as stand-ins for centuries. These include glass and colorless quartz, topaz, sapphire, beryl and especially zircon, among other gem materials.

The most prevalent diamond simulants today are manufactured in a laboratory, usually involving the use of powdered ingredients that are heated to a melting point and then cooled to solidify.

IMPORTANT TIP: Simulated diamonds are not the same as synthetic diamonds. Although both materials are produced in a laboratory, synthetic diamonds have the same chemical, physical and optical properties as natural diamonds. The simulants do not. Read more about synthetic diamonds.

14K rose gold ring is set with a near-colorless round brilliant cut synthetic moissanite.

This 14K rose gold ring is set with a near-colorless round brilliant cut synthetic moissanite, a popular diamond simulant introduced in the late 1990s. Courtesy: Brilliant Earth.

How Do Simulated Diamonds Compare to Diamonds?

Most simulants have a chemical composition and physical properties that are very different from natural or synthetic diamonds. Natural and synthetic diamonds are very durable; they are the hardest material on earth. Conversely, most diamond simulants are not nearly as tough.

  • What this means to you: Most simulants quickly show signs of wear, with scratches and visible abrasions, especially along facet junctions. Diamonds are typically more durable and longer lasting.

Diamonds have superior polish compared to simulants. They usually have more fire, brightness and scintillation. Most simulants do not have the dazzling luster that makes diamonds so coveted. These differences are usually visible to the naked eye.

  • What this means to you: Most simulants don’t sparkle like a diamond.
18K white gold ring is set with a colorless synthetic moissanite.

This 18K white gold ring is set with a colorless synthetic moissanite. Courtesy: Brilliant Earth.

Simulated Diamonds: Pros and Cons

Here’s a breakdown of the better-known diamond simulants and a summary of their plusses and minuses. Note that all can be safely cleaned with warm soapy water, but there are variable reactions to other common procedures.

Cubic Zirconia (CZ)

Copyright: GIA & Tino Hammid

Copyright: GIA & Tino Hammid

Materials:

Cubic zirconia (CZ)
Lab grown
Mohs hardness: 8 ½

Care & Cleaning:
Ultrasonic: Safe
Steam: Safe

Pros:

It is almost as brilliant as a diamond. It has good hardness.

Cons:

It scratches more easily than a diamond and appears less brilliant when dirty, so it should be kept clean.

Gadolinium Gallium Garnet (GGG)

Copyright: GIA & Tino Hammid

Copyright: GIA & Tino Hammid

Materials:

Gadolinium gallium garnet (GGG)
Lab grown
Mohs hardness: 6 ½

Care & Cleaning:
Ultrasonic: Usually safe
Steam: Usually safe

Pros:

It has similar fire to a diamond.

Cons:

Because of the low hardness, it scratches fairly easily and typically has rounded facet junctions.

Sapphire, Colorless

Natural

A colorless natural sapphire. Photo: Shane F. McClure/GIA

A colorless natural sapphire.
Photo: Shane F. McClure/GIA

Synthetic

Near-colorless synthetic sapphire. Photo: Shane F. McClure/GIA

Near-colorless synthetic sapphire. Photo: Shane F. McClure/GIA

Materials:

Sapphire, colorless
Natural or synthetic

Mohs hardness: 9

Care & Cleaning:

Ultrasonic: Usually safe
Steam: Usually safe

Pros:

It’s a hard and tough gem, so it’s extremely durable and can be worn as a center stone in a ring.

Cons:

It’s not as bright or fiery as a diamond.

Synthetic Moissanite

Photo: Robert Weldon/GIA.

Photo: Robert Weldon/GIA.

Materials:

Synthetic moissanite
Lab grown
Mohs hardness: 9-1/4

Care & Cleaning:
Ultrasonic: Safe
Steam: Safe

Pros:

It’s the hardest of all the diamond simulants and has more fire than diamond.

Cons:

Early material was slightly yellowish or greenish; colorless material is now available. It may have a slightly fuzzy appearance in some directions because of doubling of the back facets.

Synthetic Rutile

Copyright: GIA & Tino Hammid

Copyright: GIA & Tino Hammid

Materials:

Synthetic Rutile
Lab grown
Mohs hardness: 6 to 6 ½

Care & Cleaning:
Avoid ultrasonic and steam cleaners

Pros:

It is quite brilliant and has lots of fire.

Cons:

Because of the low hardness, it scratches fairly easily and typically has rounded facet junctions. It may have a fuzzy appearance because the back facets reflect as double images (like double vision). It is often slightly yellowish.

Yttrium Aluminum Garnet (YAG)

Photo: Robert Weldon/GIA.

Photo: Robert Weldon/GIA.

Materials:

Yttrium aluminum garnet (YAG)
Lab grown
Mohs hardness: 8-1/4

Care & Cleaning:
Ultrasonic: Safe
Steam: Safe

Pros:

It has good hardness.

Cons:

It lacks the distinct fire and luster of a diamond.

The Mohs Scale rates the hardness of gems and minerals, with diamond at the top – a 10. As the above chart shows, no diamond simulants are as hard as a diamond. So they are more vulnerable to scratching and abrasions. Extra care must be taken when they are worn.

“A Drop of Tear” ring in oxidized sterling silver with a colorless zircon.

Not for the faint of heart, here’s a very edgy take on the classic engagement ring: Selda Okutan’s “A Drop of Tear” ring in oxidized sterling silver with a colorless zircon. Courtesy: Selda Okutan

Are Simulated Diamonds Good or Bad?

Ultimately, there is no good or bad when it comes to expressing love. It is a matter of the heart. But the limitations of your budget may play a role in your decision about what product to buy. Simulants are more affordable than diamonds and can serve as a placeholder until you can purchase a real diamond. And in some cases, a person may want to wear a simulant for security reasons, especially as a substitute for a big valuable stone.

Platinum engagement ring, featuring a 1.50 ct CZ center stone surrounded by 1.40 carats of diamonds

This platinum engagement ring, featuring a 1.50 ct CZ center stone surrounded by 1.40 carats of diamonds, is an example of how a diamond imitation might serve as a placeholder for a future diamond. Courtesy: Coast Diamond

On the downside, simulated diamonds don’t have the rich history and psychological heft of diamonds. You’ll rarely hear of someone passing a simulant down to another family member, but there are countless stories of grandmothers giving their engagement rings to their granddaughters. So giving a diamond is taking part in a treasured tradition.

7.5mm synthetic moissanite in 18K rose gold

This 7.5mm synthetic moissanite in 18K rose gold looks stately and elegant. Courtesy: Brilliant Earth

Whatever material you choose, be it a diamond or an imitation of one, it’s important to know exactly what you’re buying. A reputable retailer should always tell you this since your choice will have a direct effect on price and the stone’s long-term care. If you’re shopping for a diamond, and not a simulant, then asking your retailer for a GIA Diamond Grading Report will be your best assurance of the gem’s authenticity and quality.

Simulated diamonds certainly have a place in the jewelry market – as long as they are properly disclosed as simulants and you, the customer, fully understand that the product you’re buying isn’t a diamond.

Wondering how to tell if a diamond is real?