Last updated on June 14, 2021
While the appearance of diamond simulants is similar to that of real diamonds, they are not diamonds. There are various terms such as diamond simulants, imitations and alternatives used in the industry, so it is important to know what diamond simulants are and how they compare to the real thing.
What Are Diamond Simulants?
A diamond simulant, also known as simulated diamond, diamond imitation, imitation diamond and diamond alternative, is a stone with gemological characteristics similar to those of a real diamond.
As the name suggests, diamond simulants are used in jewellery production to imitate real diamonds. While they look similar to the real thing, diamond imitations always have a different chemical structure and physical properties from those of a diamond. A trained gemologist with the appropriate equipment will always be able to tell a diamond simulant from a real diamond, even by visual inspection.
Diamond simulants can be both natural and synthetic. Among the most popular synthetic simulants are rhinestone, cubic zirconia (CZ), moissanite, lab-grown white sapphire, lab-grown spinel, rutile, strontium titanate, YAG (yttrium aluminium garnet) and GGG (gadolinium gallium garnet). Natural diamond alternatives include quartz, zircon and topaz.
It is important to note that lab-grown diamonds, also known as synthetic, man-made, cultured or cultivated diamonds, are not diamond simulants. They have the same crystal structure and chemical composition (100% carbon) as natural/mined diamonds.
Moreover, synthetic diamonds have the same physical and optical properties as natural stones, meaning they have the same hardness (10 on the Mohs scale) and refractive index (2.417 – 2.419). The only difference between lab-grown and natural diamonds is that lab-grown diamonds are created synthetically in laboratories, while natural ones are mined from the earth.
How to Tell a Diamond Simulant
To be considered a diamond simulant, a stone should possess certain diamond-like properties. While most simulants have properties that closely approach real diamonds, they have one or more features that help to tell them apart from diamonds. Below are the characteristics on which diamond imitations differ from the real ones.
Hardness is probably the most important characteristic that helps differentiate simulated and real diamonds. Diamond is at the top of the Mohs scale of mineral hardness with a rating of 10. It is the hardest naturally occurring mineral known, meaning it is highly scratch-resistant and has perfectly crisp and sharp facets.
Diamond simulants can never come close to real diamonds in terms of hardness. Most simulants can be easily identified by their external flaws and poor polish. Simulants scratch, crack, chip and break easier than diamonds.
Fire and Brilliance
Diamonds are cut to bring out their fire and brilliance. Both properties are strongly affected by the cut quality of the stone, but they are the result of the diamond’s high refractive index of 2.417 – 2.419 and dispersion of 0.44.
Very few simulants have a close refractive index and dispersion, meaning they appear comparatively dull and “lifeless”. Other simulants such as cubic zirconia and moissanite, exhibit a lot more colourful sparkle than diamonds, making them easily distinguishable for an experienced observer.
Colour and Clarity
Most colourless diamonds are tinted with some degree of yellow or brown, whereas imitation diamonds usually come completely colourless. If you put a simulant next to a real diamond, the first will look very bright and white in comparison.
The clarity is another factor to tell a diamond simulant. Most real diamonds have certain internal and external flaws which are part of their nature. Artificial simulants are usually internally flawless as they are grown in a controlled environment. Natural diamond simulants come with inclusions, but these flaws are often unlike to be seen in real diamonds.
Diamond fluorescence is the ability of the stone to emit visible light and change its colour when subjected to ultraviolet (UV) rays from sources like the sun and fluorescent lamps. Diamonds may fluoresce a blue, yellow, green, mauve and even red of varying intensity.
Artificial diamond simulants can also fluoresce, but since they are grown in labs, they tend to have uniform properties and fluoresce identically, without showing the varying intensity of colours. In a multi-stone piece of jewellery, one would expect to see different colours and intensities of fluorescence. If all the stones emit identical light, they are unlikely to be real diamonds.
Thermal and Electrical Conductivity
Since real diamonds and diamond simulants have different chemical structure, they conduct heat and electricity differently. Meaning, heat or electricity will pass through a diamond in another way than it would through white sapphire, for example.
These properties help to separate diamonds from their imitations using a diamond tester. To test if a diamond is real, you need to place the tip of the tester on the stone and detect the rate at which heat or electricity moves through the gem.
However, it is important to mention that diamond testers measuring only the thermal conductivity of a stone cannot tell a real diamond from moissanite as these two stones are very similar when it comes to interaction with heat. In such a case, diamond testers that measure electrical conductivity are more accurate as diamonds and moissanites conduct electricity differently.