Diamond Simulants Explained: Cubic Zirconia and More
At first glance, diamond simulants like cubic zirconia and moissanite may appear similar to natural diamonds, but their composition tells a different story. Unlike diamonds, which form from crystallized carbon deep within the Earth over billions of years, simulants are made from entirely different materials, such as zirconium dioxide or silicon carbide, in factory settings. These distinctions impact everything from durability and brilliance to how they interact with light—details that trained experts and modern diamond testers can easily detect. Below, discover the difference between natural diamonds, lab grown diamonds, and diamond simulants.
Understanding the Difference Between Natural Diamonds, Lab Grown Diamonds, and Simulants
A diamond simulant may sparkle, but it’s not the real thing. Designed to mimic the appearance of a natural diamond, simulants lack the unique composition and enduring rarity that make natural diamonds so extraordinary. While they may look similar at a glance, trained experts and diamond testers can easily tell them apart. Lab grown diamonds, while man-made like simulants, are made of crystallized carbon and share similar physical and optical properties as natural diamonds, making them harder to distinguish.
Diamond Simulants
Diamond simulants are man-made stones that mimic the look of natural diamonds but lack crystallized carbon. They’ve been around for centuries, designed to replicate the beauty of natural diamonds without the rarity and value. Diamond simulants are easier to identify with basic tests, given their different chemical compositions. They don’t match the properties of real diamonds.
Lab Grown Diamonds
While they look like natural diamonds, lab grown diamonds (also called synthetic diamonds or man-made diamonds) are made from crystallized carbon atoms, not a simulant, and hold a different value. Lab grown diamonds are created through two primary methods, both using a diamond seed to start the process: High Pressure High Temperature (HPHT), which mimics the natural conditions of the Earth’s mantle, and Chemical Vapor Deposition (CVD), where a carbon-rich gas is used to grow diamond crystals layer by layer. Lab grown diamonds can be difficult to distinguish from natural diamonds without expert analysis or specialized testing tools since they have similar properties as natural diamonds.
How to Identify a Real Diamond vs Lab Grown or Simulants
As simulants become more affordable due to advancements in technology, understanding the differences between natural diamonds, lab-grown diamonds, and simulants is essential for making informed purchases. They may look similar but have very different values. Learn more below about how to determine if your diamond is real.
How to Tell If Your Diamond is Real
Expert Identification
Experts can easily spot the difference, as simulants don’t reflect light like real diamonds.
Scratch Test
Natural diamonds are the hardest material and rarely get scratched. Multiple scratches may indicate a fake.
Fog Test
Breath on the stone – if it doesn’t fog, it’s likely real. However, this isn’t foolproof.
Heat Conductivity Tester
A budget-friendly tool that can confirm if it’s a diamond by testing its heat conductivity.
Popular Diamond Simulants
Cubic Zirconia
One of the most common diamond simulants is cubic zirconia (CZ), which is a synthetic material made of zirconium dioxide. Cubic zirconia was first mass-produced in the 1970s as a more affordable alternative to diamond engagement rings and diamond jewelry. Cubic zirconia has a hardness of 8 on the Mohs scale, which is less than the hardness rating of a diamond which is 10. Cubic zirconia has a high refractive index, meaning it reflects light in a way similar to a diamond, giving it a sparkle that few simulants had before it. Regardless, any expert can tell the difference between a CZ and a natural diamond.
Moissanite
Another common diamond simulant is synthetic moissanite. While moissanite is a naturally occurring silicon carbide, the man-made copy is what is usually used as a diamond simulant. Moissanite has a hardness of 9.25 on the Mohs scale, so it is more durable than most diamond simulants. However, moissanite is also “doubly refractive,” which means it reflects light differently than a natural diamond, making it easy to distinguish.
White Sapphire
Lab grown white sapphire is another relatively common diamond simulant. White sapphire can also be a naturally occurring gemstone; its man-made copy is more common as a diamond simulant. Like other man-made replicas, its natural version is far more valuable. White sapphire is made of aluminum oxide and has a hardness of 9 on the Mohs scale, which makes it one of the hardest materials after an actual diamond. White sapphire reflects less light than a diamond and often has a more ‘milky’ appearance, making them easily distinguishable with the naked eye.
Lab Grown Simulants
Other less common diamond simulants include lab grown spinel, glass, YAG (yttrium aluminum garnet), and GGG (gadolinium gallium garnet). All of these simulants are also lab grown or man-made and fail to match a natural diamond’s hardness level of 10 on the Mohs scale of hardness, meaning they are less durable. They also have different visual properties that make them easily distinguishable from natural diamonds.
Quartz, Zircon, and Topaz
Diamond simulants can also be found in nature. These natural gemstone simulants also mimic the visual properties of a diamond and include quartz, zircon, and topaz. Although natural, their relative abundance to natural diamonds means they are still far less valuable. They also fall behind diamonds in terms of hardness, with quartz a 7 on the Mohs scale, zircon a of 7.5, and topaz with a hardness of 8. Like man-made simulants, their visual properties are dissimilar enough from diamonds to make them easily distinguishable.
