Lab-grown Diamonds vs Diamond Simulants

There are countless types of diamonds on the market that can have you comparing stones for hours. The diamond industry is so vast and sometimes the lines can blur between real diamond rings and synthetic/lab diamond rings. Moreover, even for novice gemologists, it’s hard to decipher between lab grown diamond rings and diamond simulants.

What are diamond simulants?

Diamond simulants, also known as imitation diamonds, are stones that look like real diamonds but have different physical properties. Popular diamond simulants are the following: cubic zirconia and moissanite.


Commonly referred to as CZs, cubic zirconia is a synthetic gemstone made of the cubic crystalline form of zirconium dioxide, discovered in 1892. Naturally grown cubic zirconia is rare and all cubic zirconia used in jewellery is man-made.


Moissanite was first Discovered by Nobel Prize-winning French scientist Henri Moissan in the creator of a fallen meteor in 1893. Moissan first thought that he found diamonds in the meteor site, but later realised that the stone was made of silicon carbide. As genuine moissanite is incredibly rare, the moissanite diamond used in jewellery is man-made.

While good quality diamond simulants such as cubic zirconia and moissanite may look like real diamonds, they are very different from lab grown diamonds.

Moissanite and Cubic Zirconia vs Lab-grown Diamonds

Physically:  Diamonds are the hardest natural substance and a 10 on the Mohs scale of hardness. Since lab grown diamonds have the same physical properties as naturally grown diamonds, they are also a 10. Moissanite ranks at an 9.25, while cubic zirconia is an 8.5 on the scale. While these numbers are not low, diamond simulants will become more easily damaged than actual diamonds.

Visually: Who isn’t captivated by the outstanding brilliance of diamonds? A lab grown diamond will produce this signature sparkle while diamond simulants cannot achieve this brilliance because light travels differently throughout those stones. Moissanite is known to have a “disco-ball” effect because when light hits the stone it makes rainbow flashes.

Colour Grade: As one of the 4C’s of diamond grading, colour grade refers to the amount of yellow or brown hues that a white diamond has. While natural diamonds can come in an array of colours, so do lab grown diamonds. Cubic zirconia is colourless and standard moissanite is about a K colour. However, some jewellers sell premium quality moissanite, which has better colour grades.

Clarity Grade: Another member of the 4 C’s of diamond grading, clarity grade refers to the number of imperfections in the stone. Natural and synthetic diamonds can have an array of imperfections. Cubic zirconia, on the other hand, does not have any imperfections, and moissanite has a midrange clarity grade.

Cut Grade: Cut grade refers to how well cut a diamond is. Each stone can have different cut grades depending on the skill of the person who cut them. The cut grade heavily determines how a diamond reacts to light.

Carat Weight: The final member of the 4C’s refers to how heavy the diamond is. Lab grown diamonds and diamond simulants can come in any carat weight.