How Do Labs Make Synthetic Diamonds?

February 28, 2020 - Jewelry & Luxury Items

When it comes to pawning diamonds, it helps to know the fundamental background information on diamond synthesis.

This knowledge will help you from getting ripped off! You’ll want to know how labs make synthetic diamonds, the difference between synthetic diamonds and natural diamonds, and the difference between a simulant and a diamond. There are dozens of geological terms you’ll want to verse yourself with to be able to understand your jewelry appraiser. This is especially true for consumers who are visiting pawnshops!

Unlike retail stores, pawnshops take extra precautions to ensure the authenticity of the diamonds they carry. Retailers typically only carry certified diamonds. The Gemological Institute of America (GIA) or other certifying institutions can provide a certificate to let consumers know exactly what they’re purchasing. Laser inscriptions are also a dead giveaway as to what your jewelry is composed of since a synthetic diamond can run up to 40% cheaper than a real diamond! This means it literally pays to know the difference!

Reputable pawnshops will have GIA trained & certified staff who can appraise jewelry with, or without a certificate. This ensures that dealers can’t accidentally buy, sell, or distribute a pawn loan of worthless gemstones under the guise of a diamond. To find a GIA-certified pawnshop, use PawnGuru!

How are Synthetic Diamonds Made?

There are two ways to create a synthetic diamond in a laboratory. The first way is a technique called High Pressure High Temperature (HPHT). This process begins with a seed of diamond material. The process works with by applying high pressure and temperatures to the seed material, hence the name. This mimics the same process that would happen deep within the crust of the Earth. Only this way, full diamonds grow in 8 to 13 weeks instead of 3 billion years.

Lately, a newer technique called Chemical Vapor Deposition (CVD) is being used by laboratories to grow synthetic diamonds. The CVD process begins with filling a chamber full of carbon-rich vapor. The diamonds grow from carbon atoms being extracted from the gas remnants which are then deposited on wafers of diamond crystal. This process forms the crystalline structure as the gemstones grow layer by layer on the wafer. A CVD-diamond takes anywhere from 8 to 10 weeks to fully grow.

What Exactly is a Synthetic Diamond?

Simulants Vs. Synthetic Diamond

There are several varieties of gemstones that are advertised as diamonds but are not even considered a ‘synthetic diamond.’ Precious gemstones that are lab-made and created to mimic the look of a diamond are what’s known as ‘simulants.’ A simulant might look nearly identical to a diamond at first glance but because the gemstone has different chemical properties and composition—it’s easy to spot than a synthetic diamond which has the same properties as a real diamond.

Cubic Zirconium

The most prevalent simulant is Cubic Zirconium or CZ. A single carat stone of CZ can retail at $20 while a diamond of the same carat, color, cut, and clarity will be worth thousands. CZ first appeared on the market in the 1970s. As labs found easier and cheaper ways to make CZ, the stone became increasingly less rare and therefore less valuable.

There are simple tricks to decipher whether you have CZ or a diamond. The simplest is to breathe against the gemstone. Since diamonds are efficient heat conductors the fog will dissipate immediately. If the fog lingers on the gemstone you most likely have a Cubic Zirconium gemstone.


Another common simulant is called Moissanite and is a quarter of the price of a true, mined diamond. There are 3 degrees of Moissanite: Classic Moissanite, Forever Brilliant Moissanite, and Forever One Moissanite. The degree of Moissanite is contingent on how the stone measures up against a GIA-certified diamond. Diamonds are graded in terms of clarity, cut, color, and carat—otherwise known as the 4Cs.

A single carat GIA-certified diamond with high grades on the 4Cs will be valued around $4,000 while a Classic Moissanite’s worth is $269. A Forever One single-carat Moissanite can reach as high as $599. Just like CZ, it’s easy to spot the differences between diamonds and simulants because they have a different chemical composition.

What’s the Difference Between “Synthetic” and Natural “Composition” Diamonds?

Understanding the definition of a synthetic diamond boils down to terminology. A synthetic diamond is made by humans, in a laboratory, while a naturally composed diamond is mined from the Earth.

Since synthetic diamonds are made emulating the same factors and materials—compressed carbon & heat—as naturally composed diamonds they share the same crystal structure and chemical composition. In terms of chemical properties, they are the same. They are both diamonds. They are both forever. This means the only real distinction is one was made in a lab while the other was made naturally. Even a jeweler won’t be able to visually distinguish between the two. You will need specialized equipment to verify the distinguishing details.

Synthetic diamonds are less rare and thus less valuable than naturally occurring, mined diamonds. However, since lab-grown diamonds are made in a sterile, controlled environment they have fewer flaws known as inclusions than a natural diamond. Still, human labs have different inclusions than the naturally formed diamonds so there are still ways for GIA-certified appraisers to tell with proper equipment.

To find a GIA-Certified appraiser, use PawnGuru! With a listing form PawnGuru you can also find a reputable dealer where you can buy, sell, or pawn diamonds!

David Stiebel

David Stiebel is one of the cofounders of PawnGuru. David was educated at MIT, where he studied Math. He subsequently worked at Bain as a data scientist before starting PawnGuru in 2015. He started PawnGuru to build a better tool for pawn shops and consumers to connect.

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