Beware of diamond simulants if you are after buying a real genuine diamond!

Here we will try to teach you about the different ways diamonds are artificially made in labs. On the other hand for those who want a cheaper buy this might be a good choice if you are making an informed decision.

As the market for diamonds continues to grow and diamonds increase in value and price, many people have looked for options to replace these diamonds. These imitations or simulants can be natural, artificial or a combination of the two and are used to replace diamonds at much lesser costs.

Gemisimo Advice: Always Check the Diamond Report prior to buying!!!

It is therefore all the more important that diamond buyers be aware of the various diamond simulants available in the market today. It is also important to understand the difference between synthetic diamonds and simulants, as many often confuse the two terms. Synthetic diamonds are quite rare and have a chemical composition similar to natural diamonds. Simulants on the other hand have a chemical composition much different from diamonds. Secondly while synthetic diamonds are produced in laboratories in sizes suitable for cutting, simulants may be natural, artificially or a combination of the two.

History

The history of diamond simulants is as old as the history of diamonds . For many years, the options to replace diamonds were few. The most popular options during 1700 were natural stones that would shine like diamonds. These stones were usually made out of glass, the refractive index of which was increased by using lead, thallium and alumina. During the 1900s, many artificial simulants arrived on the scene. These included synthetic white sapphire and spinel. During 1947 optically enhanced simulants like synthetic rutile arrived on the scene followed by the commercial launch of in strontium titanate 1955. While each simulant was launched with more enhanced diamond like features , drawbacks were also quick to be discovered. Strontium titanate was soft and brittle and in the 1970s began being replaced by synthetic garnets. Yttrium aluminum garnet (YAG) was introduced in the late 1960s followed by Gadolinium Gallium Garnet (GGG). In 1976 Cubic Zirconia and many other materials, fast entered into the simulant scene in a big way, and continue to be popular diamond simulants even today. We will try to cover all these in this article.

Diamonds vs. diamond simulants at a glance

Properties of diamond

Chemical composition: Carbon

Hardness on Mohs scale: 10

Refractive index: 2.42

Specific gravity: 3.52

Natural simulants

This section comprises of natural minerals that resemble diamonds when they are cut. However there are very few such minerals, as the presence of trace impurities in such materials often reflect color. Natural simulants used through history include,

Natural zircon (ZrSiO4)

Natural zircon was popularly used as a simulant during ancient times. The white color of the crystal was obtained by heating zircon of colors like yellowish-brown and green. The stone was noted for its good brilliance and fire. However, natural zircon proved to be very different from diamonds on closer examination. The simulant's hardness is approximately 7 and can easily be scratched by topaz. Secondly, this simulant also shows wear on the girdle edges and lesser brilliance.

Colorless scheelite

This was less prevalent than natural zircon but was also used as a simulant. While the stone enjoyed high dispersion, it demonstrated less hardness, equal to 4.5. Also there is comparatively less availability of natural gem quality scheelite and synthetic scheelite has been more popularly used.

Carbonate cerrusite

These naturally occurring crystals also enjoy high luster and dispersion, making them look very attractive. However these are rarely used as diamond simulants as they are soft, fragile, difficult to cut and have a high density.

Sphalerite

Also known as zinc blende, this material has a high refractive index and dispersion. On the flipside however, this stone has a low hardness and a perfect dodecahedral cleavage.

Topaz

With a high hardness of 8, topaz was a popular diamond simulant for many years. However, the stone has low refractive index and because of less fire than diamonds, today it is rare to see the usage of topaz. Gemologists can also differentiate between topaz and diamonds because the inclusions present in topaz are very different from those found in diamonds.

Artificial simulants

Artificial simulants have grown in popularity and usage since many years as these are easy to produce and demonstrate results much closer to real diamonds.

Synthetic white sapphire

These have been used for a long time as simulants and have high hardness of 9. However the stone has a dull shine and because it is anisotropic, it can easily be detected through a polariscope. The stone has a refractive index that falls within the range of a refractometer and on observation through a loupe, one can see air bubbles.

Synthetic spinel

This was used as a successful diamond simulant for a long time, for its hardness of 8, but its fluorescence in bluish white hue under LWUV and a blue green hue under SWUV, have made it easily detectable from diamonds.

Glass

Glass has been a popular diamond simulant, mainly because it has been possible to give it brilliance and shine with different compositions. However glass is quite different from diamonds and examination with a polariscope can show the difference. Air bubbles can be a giveaway and glass also often shows swirl marks.

Synthetic rutile (TrO2)

This has a high refractive index as compared to diamonds and thus gives a high brilliance. However rutile is anisotropic, and its great fire (eight times more than diamonds) makes the stone appear too colorful. Also this simulant is much softer than diamond, ranging at point 6 on the Mohs scale, making it easier to differentiate from diamonds.

Strontium titanate (SrTiO3)

This simulant looks very much like a diamond, but is not in much use today mainly due to the usage of Cubic Zirconia. The stone is different from diamond because of its high quantity of fire, which makes the stone appear highly colorful. Also it is very soft, a factor that does not allow for giving it a good polish and finish.

Yttrium Aluminum Garnet (YAG) Y3Al3O12

This simulant proved to be highly successful and much used when it was first introduced in the market. The main factors that make YAG resemble diamonds is its colorlessness, high hardness and good refractive index. The way to differentiate a YAG from diamond is to observe it under a loupe. Small air bubbles and polishing lines typical to YAG can be observed in this manner.

Gadolinium Gallium Garnet (GGG) Gd3Ga5O12

The properties of this simulant also resembles those of diamonds quite closely, making the stone a successful simulant. These properties include a high refractive index and fire. However expert gemologists can differentiate a GGG from a diamond through its brown undertone and softness. Air bubbles and triangular leaflet like inclusions can also be seen in GGG.

Cubic zirconia

In today's diamond market, cubic zirconia is the most popular and most effective diamond simulant. This is the precise reason why, this stone is produced in high quantities. The stone is difficult to distinguish from diamonds because it disperses light similar to diamonds. Also this has a high refractive index, hardness (8 on Mohs scale) and dispersion. Gemologists differentiate cubic zirconia by measuring the specific gravity of the stone, which is higher than that of diamonds. Another test that many gemologists follow is to bring the stone to their tongue. Diamond is very cold to touch while cubic zirconia does not feel as cold. Vapor tests or rapidographs are other methods used to differentiate diamonds from cubic zirconia.

Composites

Besides natural and artificial simulants, diamond imitations comprising of both natural and artificial elements are also present. One popular example of such a combination is doublets. These stones have several parts, starting from two onwards. Cases of such simulants exist where a thin layer of diamond is attached to an artificial stone like cubic zirconia or YAG. Another example of composites, involves doublets with cubic zirconia core covered with amorphous diamonds created in the laboratory. These stones are highly deceptive in nature as a quick examination only reveals the thin layer of

How experts differentiate diamonds from simulants

Diamonds are known for their hardness and brilliance. Based on diamond's intrinsic special features, gemologists follow one or a combination of the below measures to identify whether a particular stone is a diamond or not.

• Diamond has the highest degree of hardness on the Mohs scale, which implies that a diamond can only be scratched with a diamond. Sapphire is the next hardest stone on the scale and gemologists usually scratch the stone to be tested with sapphire. Diamonds do not get scratched by sapphires, while other imitations usually do.
• Diamonds are also noted to have lower specific gravity than most other imitations. Thus when stones to be tested are put in di-iodomethane, a heavy liquid, diamonds sink slowly as compared to other imitations that comparatively sink faster.
• Checking for inclusions typical to diamonds and other imitations also assists gemologists in identifying diamonds.
• Spectroscopic examinations are also conducted and diamonds reveal their own characteristic absorption bands. Reflectometers are also used to check the degree of light reflected from the stone's surface.

However there are many imitations that one must be aware of. Buying diamonds from trusted sellers is probably the first step that careful buyers must take. Secondly purchasing certified diamonds is also important.

Finally in case of doubt, diamond buyers always have the right to get the diamonds tested at a local diamond laboratory of repute. Diamond imitations are prevalent and often difficult to detect. However today laboratories do have sophisticated techniques to make the process easier.

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Artificial simulants  CZ  Fake Diamonds  Natural simulants  Synthetic