Being aware of the types of diamond simulants that exist can protect you as a consumer of real diamonds. This is perhaps the number one concern of most people when buying a diamond. Is it real?
Well the thing about diamonds is that its properties are so unique that it is pretty hard to fake. I will be talking about ways you can quickly tell whether a stone is likely to be a diamond or not in a bit. Apart from the peace of mind knowing how to distinguish fakes gives you, I think that during this process you will actually appreciate the uniqueness of diamonds more, not just from a technical point of view, but more importantly from a visual aspect.
Some of you, after gaining an understanding of diamond simulants, may think it is not worth it to buy a diamond. After all, you will see that many diamond simulants are very beautiful in their own right. This tutorial is designed to help you understand why a diamond costs what it does in a different way to what I have discussed with you before. I will explain to you the differences between these diamond simulants and real diamonds and hopefully you will see that the pricing between a low quality simulant, a high quality simulant, and a diamond is not much different to the pricing between a high quality and low quality diamond.
I think that by calling a gemstone a simulant or, worse, a ‘fake’ diamond is in many ways unfair. I much prefer giving credit to these stones for what they are and recognising their potential to at least be compared to diamond. As you all know by now, the reason a diamond has its brilliance, fire, and sparkle is because of its cutting even more so than by the fact that it is a diamond. Being a diamond only gives it that potential to be one of the most brilliant gemstones, the cutting determines whether it actually ends up being one. With this in mind, it is not very difficult to imagine that the same applies for simulants.
The main things that influence the cost of a diamond simulant are:
- The cost of the raw material itself
- The cost used to cut the simulant
- The cost used to market and sell the simulant
In real diamonds the cost of the raw material is the most significant factor, but in simulants the costs are more to do with the cutting or the branding. I know I don’t need to tell you that marketing and branding does absolutely nothing to make a gemstone be more beautiful, but also never underestimate the power of marketing. In the following sections, I will go through some of the more popular types/brands of simulants and compare them in regards to how well they perform as a simulant, and any important things you need to know about them.
How to Spot a Diamond Simulant
The most commonly suggested is to use the fog test. This is a simple test carried out by breathing onto the diamond. If it is a real diamond, then the fog should dissipate within a second because of its high thermo-resistivity. This method is not accurate because CZs with diamond coating, discussed below, will have a similar rate of dissipation.
Another test that is more useful is to simply draw a black dot on a sheet of paper, and put the loose diamond on top of the dot table-down. A real diamond will break up that dot completely whereas a CZ will make the dot appear more like a circle. This test requires you to have a loose diamond though and is not the most reliable.
It is much more reliable to use what you know about diamond optics to spot fakes. I will discuss later how CZ looks more ‘disco-balky’ and has rounded meet-points.
Diamond Simulant 1: Cubic Zirconia (CZ)
| Cubic Zirconia | Diamond | |
| Weight of a 1ct stone | 0.34 grams (1.7x diamond) | 0.2 grams |
| Refractive Index | 2.15 – 2.18 | 2.42 |
| Dispersion Index | 0.058 – 0.066 | 0.044 |
| Lustre | Adamantine (13.6%) | Adamantine (17.2%) |
| Cost for a 1ct D IF | US$0.20 | US$20,000 |
| Hardness (Mohs scale) | 8 | 10 |
| Fracture Toughness (Resilience) | 2.0 MPa m1/2 | 2.0 MPa m1/2 |
I start with CZ because it is probably the most common of the diamond simulants you will encounter. The Hardness measurement needs a bit of explanation, as the Mohs scale is not a linear scale and diamond is actually around 8 times harder than CZ. The general idea is that a harder material can scratch a softer material. Basically for regular purposes, only another diamond can scratch a diamond. Something you may not have known before is that because of a diamond’s hardness, it is polished so that the facets have sharp meet-points. A diamond simulant can actually be polished to have rounded corners to improve their light performance. This is one of the ways to spot a fake but requires inspection using a loupe.
Fracture toughness is a measure of a material’s resilience to cracking. You can see that diamond and CZ have basically the same resilience (these numbers are approximate). But CZ can be treated in a way that increases its resilience to almost 10 times that of diamond.
What I actually want you to focus on are the refractive and dispersion indices. The refractive index is proportional to the potential brilliance, scintillation, and lustre of a material and dispersion as you know already, is proportional to the fire. But all these numbers are meaningless unless we know what to look for.
In fact, no one that I’ve asked to compare a diamond against a well-cut CZ has been able to describe the differences, let alone be able to determine the effects of a higher refractive index in diamond. Interestingly, when asked which they preferred, I have found that most people do prefer the diamond although they usually have trouble saying why.
All I can tell you is that a well-cut CZ can be very bright, and perhaps just as bright as a diamond to many people. I own a Swarovski Signity Star that came pre-selected as part of my ideal-light set. I can tell you that the stone is very brilliant, and I have read many reports that Wink’s CZs are even better.
CZ also has a higher dispersion than diamond and this translates as more fire. Actually, the fire in a CZ is so great that it is often described as ‘disco-bally’ and one of the things done to make CZ more real is to suppress its fire. For those fire aficionados then, perhaps instead of trying to find an FIC, it may be worthwhile to see if you like some of the diamond simulants more than diamond!
CZs have had a poor reputation since its introduction in 1976. I think the reason for this is not only because it’s a ‘fake’, but rather because plain CZs are porous and readily absorb things like lotions or natural oil making it appear cloudy over time. The answer to this was to add coatings to CZ. It is these coatings that separate out each branded CZ simulant. For example, Diamond Nexus claims to use some kind of a corundum coating and BetterthanDiamond’s Ashas have an amorphous carbon or Diamond-like carbon (DLC) coating. These coatings are bonded to the CZ core at the atomic level using a process called chemical vapour deposition (CVD). Having purchased a pair of Asha earrings for my fiancé, I can personally attest to how beautiful they are. On the other hand, I have read mixed reviews about Diamond Nexus so please be careful and do your research before considering purchasing from them.
The downside of an amorphous carbon coating is that it changes the gem into a composite material that has a ‘birefringence’, commonly referred to as a double refraction. Cubic crystals like diamond and CZ on the other hand are isotropic and are singly-refractive. You don’t need to understand the technical meaning of these words; I just wanted you to understand how these composite materials differ from diamond as a crystal.
Diamond Simulant 2: Moissanite
| Moissanite | Diamond | |
| Weight of a 1ct stone | 0.18 grams (0.9x diamond) | 0.2 grams |
| Refractive Index | 2.65 – 2.69 | 2.42 |
| Dispersion Index | 0.104 | 0.044 |
| Lustre | Adamantine (20.4%) | Adamantine (17.2%) |
| Cost for a 1ct K VS2 | US$275 | US$5,000 |
| Hardness (Mohs scale) | 9.25 | 10 |
| Fracture Toughness (Resilience) | 1.8 – 2.5 MPa m1/2 | 2.0 MPa m1/2 |
Moissanite is a form of silicon carbide and was originally found in meteorites but is synthesised for gem production. You can see from the table that Moissanite actually has a higher refractive index than diamond as well as being much harder and even more dispersive than CZ. The weight and durability are pretty much the same. The problem with natural Moissanite is that it naturally has a green tint to it and the tint becomes more apparent with size. Raw Moissanite is supplied exclusively by Charles & Colvard.
Like CZ, there have been advancements in technology to enhance the look of Moissanite. The Amora Enhanced Moissanite, not to be confused with the new Amora Gem, undergoes a process that is ‘analogous to HPHT’ according to BetterthanDiamond who sells them, and ends up being up to H color for a true near-colorless Moissanite. The reason Moissanite can never be truly colorless is because even as a perfect crystal, its electrons still absorb some of the white light instead of transmitting it completely thus what is returned to your eye is not white light but colored light. It just so happens that Moissanite absorbs more purple light and therefore appears to have that green tint.
Remember: White – Purple => Red + Green + Blue – (Red + Blue) = > Green
Moissanite, and many other gemstones, are said to have a chameleon effect. The explanation is because the above equation depends on pure white light being the light source. Of course, as you have different light sources containing varying amounts of red, green, and blue, then depending on the stone, you will have differing results.
Silicon carbide has a double refraction. The double refraction is one of the easiest ways to distinguish a diamond simulant like the Asha or Moissanite from a real diamond. In a well-cut CZ, the double refraction can only noticeably be seen from the side, but it can also be seen in the face-up view if you inspect the table reflection. Under magnification, the table reflection will, rather obviously, be doubled. Without magnification, the table reflection looks more like a circle rather than the crisp star shape that is seen in a nice H&A diamond.
Diamond Simulant 3: Amora Gem
| Amora Gem | Diamond | |
| Weight of a 1ct stone | 0.18 grams (0.9x diamond) | 0.2 grams |
| Refractive Index | 2.66 – 2.71 | 2.42 |
| Dispersion Index | 0.104+ | 0.044 |
| Lustre | Adamantine (20%) | Adamantine (17.2%) |
| Cost for a 1ct F IF | US$650 | US$10,000 |
| Hardness (Mohs scale) | (9+ – 30% harder than Sapphire) | 10 |
| Fracture Toughness (Resilience) | Tougher than diamond | 2.0 MPa m1/2 |
The Amora Gem, like Moissanite is a form of silicon carbide and is not native to planet Earth. The Amora Gem is actually found naturally in large stars in temperatures that would melt natural diamond. The Amora Gem is an entirely new synthetic gemstone and has literally just become on sale. I don’t know much about this yet, but I have been following the threads over at BetterthanDiamond for quite some time. I am 4th on the waiting list for a six-carat Amora Gem, but the production and first sales of 8-9mm stones have already started.
Looking at the above table, it does seem like the Amora Gem is likely to be more brilliant, more fiery, more lustrous, and tougher than diamond. Notice that the birefringence is likely to be much lower than Moissanite, but worse than the Asha. Initial reports have noted that the double refraction is better than expected. One thing to note also is that the Amora Gem is a truly colorless gemstone so it will be an F color or above on the diamond grading scale.
Lab-made Diamonds
Lab-made synthetic diamonds have been possible for quite some time now and the Gemesis Diamond Company is the principal global distributor. Lab-made diamonds are type-2a diamonds and ironically, the initial diamonds that were created were fancy yellow colors that fetch a high premium as a natural diamond. However, lab-made diamonds are now available in the colorless range as well. Remember that lab-made diamonds are chemically exactly the same as natural diamond.
Back in early 2012, when I was looking at Gemesis’ inventory, I noticed that they did not have many 1ct+ diamonds. This has changed and it now appears they have more 1ct+ ideal cut stones, however the highest color still appears to be a G color. A 1ct GVVS2 diamond that has ideal proportions with an IGI certificate is listed as US$7,587. In comparision, the cheapest comparable 1ct GVVS2 ideal cut natural diamond on Blue Nile is listed at US$8,097. This only represents a 6.3% discount off a natural diamond and the Blue Nile diamond is graded by GIA. The fact that synthetic diamonds command such a small discount shows you how difficult and costly it is to actually produce synthetic diamonds. With such a small discount, such fewer selection, inferior grading and cutting, it is no wonder why synthetic diamonds have not become popular.
Sparkly Stones from $1 to $100,000
Here is a just-for-fun table of the approximate pricing for various sparkly stones for you to compare.
| 3mm – 4.5mm (0.15 – 0.3ct) | 6.5mm (1ct) | 9mm (3ct) | |
| Generic CZ | $1 | $5 | $10 |
| Signity Star Swarowski | $3 | $15 | $30 |
| Winfield’s ‘Wink’ CZ (Interlap) | $10 | $43 | $109 |
| Asha | $18 | $189 | $445 |
| Unenhanced Moissanite | $24 | $275 | $839 |
| Forever Brilliant Moissanite | $35 | $399 | $1299 |
| Amora Moissanite | $145 | $455 | $1379 |
| Amora Gem | $300 | $700 | $1500 |
| Lab-made Diamond | $500 | $3500 | n/a |
| Typical Natural Diamond (VG cut) | $900 | $6400($4000 JSI2) | $42000 |
| Branded/Ideal Cut Diamond | $1500 | $11500 | $80000 |
| Super Ideal H&A Diamond | $2000 | $14000($30000 DIF) | $100000 |
Conclusion
I hope you now have a better understanding of diamond and diamond simulants. The takeaway here is that there are a lot of beautiful colorless gemstones out there apart from diamond. Diamond isn’t going to be the preferred choice for everyone. What I’ve learned and hopefully something that I’ve conveyed to you is that not everything is ‘more is better’. Light return and scintillation isn’t more is better, and in my opinion fire is also not more is better. However, there is something unique about a diamond’s sparkle that to me just hasn’t yet been replaceable. I do look forward to my Amora Gem though and I will be sure to let you guys know what I think about it.