Diamonds Simulants & Synthetics – Differences Explained

Simulants by Luxuria Diamonds - flawless diamond simulant rings
Photo:  Simulants such as cubic zirconia, zircon and moissanite are frequently used in jewelry.  Seen above is a 2 carat diamond simulant engagement ring from the Luxuria jewellery brand.

What are diamond simulants and synthetics?   We regularly get questions asking what the differences are between lab-created, simulant, synthetic, cultured and hybrid diamonds.   The terminologies can be confusing.  Moreover, incorrect use of the various terminologies in online articles and adverts can mislead and cause further confusion.

As member of the Prestigious Jewellers & Watchmakers Association of New Zealand (JWNZ) and a professional member of the International Gemological Society (IGS), USA – we have an important role to play in educating consumers.

In this article we answer common customer questions about simulants and synthetics.  We hope this contribution helps demystify the differences to facilitate better informed buying decisions.

Let’s start at the beginning.  What are diamond simulants?

What are diamond simulants?

Wikipedia notes that a diamond simulant, diamond imitation or imitation diamond is an object or material with gemological characteristics similar to those of a diamond.

This is not a good definition as its unclear what is meant by the term “gemological characteristics”.

For a better definition we turn to Jewelry Notes, an online magazine dedicated to jewelry.

They state, a diamond simulant is a stone that looks similar to real diamond and shares some of its characteristics.   Although simulants are used as diamond imitations, they have a different chemical structure from real diamonds.

Some simulants occur naturally, while others are created artificially.  Examples of popular diamond simulants include cubic zirconia, moissanite, rhinestone or crystal.

Luxuria Pink Diamond Simulant Engagement Rings
Photo 1:  Diamond simulants are available in many colors.  Here is a fancy pink diamond simulant engagement ring from the Luxuria® jewelry brand.   Source:  Luxuria Diamonds

The Gemological Institute of America Inc, commonly referred to as GIA expands the list of simulants.  GIA notes there are natural simulants such as Quartz, Zircon and Topaz.   Further, there are artificial simulants such as synthetic rutile, gadolinium gallium garnet (or GGG), synthetic spinel, strontium titanate, synthetic corundum and yittrium aluminium garnet (or YAG).   That said, the most popular diamond simulants are Cubic zirconia ZrO2 (+ rare earths) and Moissanite SiC.  

Cubic zirconia commonly abbreviated as CZ and Moissanite are popular because they have a high refractive index which approaches or exceeds natural diamond and they are relatively hard.   CZ is 8 to 8.5 on the Mohs scale meaning they are slightly harder than most semi-precious gems.  Synthetic moissanite was introduced in the late 1990s as a diamond simulant. It is closer to diamond in overall appearance than any previous diamond imitation, but now it is most often sold as a gem in its own right.

Diamond and various diamond simulants - GIA
Photo 2: Natural diamond (left) and various diamond simulants: (inner left to right) synthetic rutile, gadolinium gallium garnet (or GGG), synthetic spinel, strontium titanate, synthetic corundum, yittrium aluminium garnet (or YAG), and colourless zircon. Source: GIA

Diamond Simulants are not new

It is tempting to think that diamond simulants are advent.   This is not true.  Flint glass which is glass with lead, alumina, and thallium to increase RI and dispersion dates back to 1700.  When freshly cut they can be surprisingly effective diamond simulants.  Known as rhinestones, pastes, or strass, glass simulants are a common feature of antique jewelry.

In the period of 1947 – 1970 a number of new simulants were introduced.   These included synthetic rutile and strontium titanate.  The success of synthetic rutile was hampered by the material’s inescapable yellow tint.  Further synthetic rutile had too much life when cut with a RI & dispersion much higher than diamond.   Strontium titanate was much closer to diamond in terms of refractive index and dispersion.   However, Strontium titanate was fragile being only 5.5 on the Mohs scale.

The Introduction of Cubic Zirconia

1976 saw the introduction of Cubic zirconia or CZ.   CZ quickly dominated the diamond simulant market and it remains the most gemologically and economically important simulant.  Cubic Zirconia is a cubic form of zirconium oxide that is created in a laboratory, thus it is not a mineral.  Synthesized zirconium oxide, cubic zirconia, is hard (8.5 on Mohr’s Scale of Hardness), optically flawless and usually colorless.   Since CZ is transparent, it is often faceted. It can be made in nearly any color and can be faceted into many cuts.

Because of its low cost, durability, and close visual likeness to diamond, CZ has remained an important diamond simulant.  CZ really took off in the 1980’s when Swarovski & Co., a world-renowned Australian producer of leaded crystal, began producing cubic zirconia for mass consumption.

Simulants from Luxuria - Engagement Rings
Photo 3:  A well cut cubic zirconia in nicely finished mounting will look better than a poorly cut diamond in a cheap mounting and will be much more affordable.  Seen here is a 2.04 carat solitaire diamond simulant engagement ring with matching 0.37 ct.t.w. half eternity band.   Source:  Luxuria Diamonds


CZ finally met some competition in the late 1990’s with the introduction of Moissanite.  Moissanite was introduced to the jewelry market in 1998 after Charles & Colvard, received patents to create and market lab-grown silicon carbide gemstones.

Moissanites advantage over CZ is hardness being 8.5–9.25 on the Mohs scale.   However, the refractive index and dispersion of Moissanite is much higher than diamond.  Moissanite thus has more of a rainbow sparkle compared to a diamond.   This is because of how it refracts light when it hits the surface.  The give-away is that diamond tends to emit a colorless sparkle or flashes of light instead.

While Moissanite is considerably more expensive that cubic zirconia it is typically 1/10th of the price of natural diamond.   Although Moissanite is a diamond simulant it is most often sold as a gem in its own right.

Difference between Synthetic Diamonds & Diamond Simulants

1.  Synthetic Diamonds

There seems to be a great deal of confusion about the differences between synthetic and simulant diamond.

One of the reasons for this confusion is that many of the companies that are selling fake diamonds are purposely vague.   Some work hard to not say what their product really is – cubic zirconia for example.  Some marketers make efforts to imply their product is just a different form of diamond.

The distinction starts with a basic fact:  Diamonds are diamonds and all other materials are not diamonds.

There are two types of diamonds: natural diamonds and synthetic diamonds.

  • Natural diamonds are mined from the earth and created by natural geological processes over millions of years
  • Synthetic diamonds are man-made in a laboratory using high pressure and high temperature.

Other terms sometimes used to describe synthetic diamonds include cultivated, cultured, man-made and lab-created.

In laboratories, it can take 200 hours to make a synthetic stone. If manufacturers desire a more perfect pebble (in terms of clarity and colour), the hatching time stretches to 400 hours. High pressure, high temperature (HTHP) and chemical vapour deposition (CVD) are the two methods used.

CVD and HPHT grown synthetic diamonds - GIA
Photo 4:  CVD- and HPHT-grown synthetic diamonds occur in a variety of colors depending on the growth conditions and post-growth treatments. While their final faceted appearances may be similar, the crystals produced from the two techniques are usually quite different.   Source:  GIA

While the term synthetic may sometimes be associated by consumers with imitation products, synthetic diamonds are made of the same material as natural diamonds—pure carbon.  Gem-quality diamonds grown in a lab can be chemically, physically and optically identical to naturally occurring ones.

The big draw is price.  It used to cost $4,000 in 2008 to produce a carat of diamond in a lab.  This figure is down to $300-500 per carat, noted a Bain & Co report in 2018.  Among smaller stones, lab diamonds are priced at a mere 25% of what a natural diamonds.  If customers want them, then the growth in acceptance and sales of synthetic diamonds is inevitable.

2.  Diamond Simulants

In contrast, diamond simulants merely look like diamonds.   Diamond simulants do not have the physical or chemical properties of diamond.   While some diamond simulants can be created by nature, quartz and white topaz for example, most are man-made.  Examples of man-made diamond simulants are cubic zirconia and Moissanite.

Much of the confusion in recent years stems from the marketing of the various brands of cubic zirconia.  Every brand touts itself as the best diamond simulant while usually avoiding admitting the material is cubic zirconia.  As a result, the shopper who reads the advertising about these brands is not sure what material they are considering and often confuses them with synthetic diamond.  Just because cubic zirconia is man-made and therefore synthetic, does not make it synthetic diamond.  However, when you read the marketing literature on the various brands of cubic zirconia, it is obvious that those companies try to confuse shoppers into thinking they are some form of diamond.

Diamond Simulants - Emerald green CZ ring - Luxuria
Photo 5: Cubic zirconia and other diamond simulants come in various colors. Sometimes these colour simulate other precious gemstones, for example emerald, sapphire & ruby. Seen here is a pear shaped green emerald simulant ring with white diamond simulant shoulders. Source: Luxuria Diamonds

Diamond hybrids

A diamond Hybrid tries to create the look and feel of a natural diamond by combining man made diamond crystals and a non-precious core.  The layer content, the infusion technique and the core can all vary.   The core is usually cubic zirconia, ceramic or crystal.  The core is typically layered with grown amorphous diamond.  This is composed of tiny diamond crystals which fuse together resulting in the final product

According to, the term “diamond hybrid” is usually used to describe the Amorphous Diamond Treatment (ADT) process used in the Asha® diamond simulant.  A cut and polished cubic zirconia (CZ) stone is blasted with microscopic diamond crystals to form an extremely thin layer of material that is a combination of the cubic zirconia and the infused diamond crystals.

Another brand offering diamond hybrids is Diamond Nexus Labs.   Diamond Nexus says their process is proprietary.  However, despite consumer reviews and other marketing materials claiming its uniqueness, tests according to have shown their product is simply cubic zirconia with diamond “dust” impregnating the surface.

It is difficult to determine what real benefits are provided by hybrid diamond processes.  Some claim the process results in an increase in Mohs hardness.  Others claim the hybrid possesses the most realistic, natural looking brilliance you will ever see from a diamond alternative.   Such claims are dubious.   Diamond hybrid simulant rings are premium priced, often 5 to 10 times their CZ equivalents.

How to tell the difference between diamonds, synthetics, simulants & hybrids?

It is easy for a gemologist to determine the difference between diamonds (natural or synthetic) and various diamonds simulants.

However, for the untrained eye telling the differences is not so easy.   Furthermore, marketing adverts can mislead.

Because the optical and physical properties of today’s synthetic diamonds are nearly identical to those of natural diamonds, identifying synthetic diamonds is complex.  Only a gemological lab with equipment that allows for advanced testing techniques can make an authoritative determination if a diamond is natural or synthetic.  Synthetics can be distinguished by spectroscopy in the infrared, ultraviolet, or X-ray wavelengths.   Similarly heat conductivity tests will reveal the core of a hybrid diamond is non-precious.

To the untrained eye, cubic zirconia looks very similar to a good quality diamond.  However, CZ has slightly less brilliance or sparkle than a diamond and more fire or flashes of color.  That said, the overall visual effect is so similar that it can even fool a trained gemologist on occasion, but other tests can easily differentiate cubic zirconia from diamond.   One great difference between cubic zirconia and diamond is weight; CZ is about 60% heavier than diamond. A piece of CZ the same size as a one carat diamond weighs about 1.6 carats.

Moissanite Engagement Rings - pear shape - Luxuria
Photo 6: Moissanite is widely considered a gem in its own right. Today most moissanite is synthetic. Moissanite is a very good diamond simulant. However, Moissanite is rarely colorless and gives a rainbow sparkle as captured in the above photo: Luxuria Diamonds

Equally, the naked eye of some astute observers can tell a difference between Moissanite and diamond. Moissanites usually have more of a rainbow sparkle.   Moissanites handle light differently from diamond, creating what is termed as “bi-refringance”.  Basically, light waves are split inside the crystal and their velocity becomes unequal, thus things appear doubled in appearance.

The end result is that Moissanite does not look like a diamond when examined closely.  Diamonds emit a combination of colorless sparkle (centre), rainbow sparkle (edges), and flashes of light.   Moissanite can sparkle too much and a giveaway is its flashy nature.   While some buyers adore this splash of color, others say the stone resembles a disco ball more than a diamond.  This effect is only heightened when the size of the Moissanite stone increases.  Although colorless diamonds project a white appearance, the so-called “colorless” moissanites may still visually appear yellowish or grayish.

Should I buy Synthetic Diamond?

There is no doubt that synthetic diamond is gaining popularity.   That said, it still represents only a small portion of global diamond sales.

Proponents of synthetic diamond are sometimes concerned that diamond mining has led to human-rights abuses.  The 2006 Hollywood movie Blood Diamond helped to publicize the problem in Africa.   Further the entry of De Beers and others into the synthetic market has improved affordability.  The price difference between Moissanite and synthetic diamond has greatly narrowed.   Economic Times reports Synthetic market prices are likely to fall to 25% of natural diamond.  Since synthetic diamond is much closer to real diamond than Moissanite – it could now be a preferable option.

Antagonists counter that the only reason you want synthetic diamonds is price.   Further, if conflict diamonds are a concern there is always the option of Canadian or Australian diamonds.  Canadian diamond is laser inscribed with the Canadian mine where it was discovered. Also keep in mind that a lot of the natural yellow diamonds come from the Argyle Mine in Australia.   Moreover, while synthetic diamonds are much cheaper, the prices are likely to continue to fall.  Synthetics may also much harder to resell in the future.   This is because around 95% (today) of diamond shoppers want natural diamond.

CVD synthetic diamonds display color brightness of natural diamonds - GIA
Photo 7: These CVD synthetic diamonds display the same color and brightness of comparable quality natural diamonds. They range in size from 0.24 to 0.90 ct. Source: Robert Weldon / GIA

Should I buy Simulated Diamond?

There is nothing wrong with buying diamond imitations as long as you are aware that they are not real diamonds.   The main attraction of diamond simulants is that they are a lot cheaper than the real deal.  In that sense they could be considered a low risk purchase.

Keep in mind though that imitation diamonds are not as hard or durable as mined or synthetic diamonds.  For example, Cubic Zirconia can get scratched. It’s considered to be a relatively hard stone, but anything that’s harder than it is, has the potential to scar its surface. Cubic Zirconia falls between 8 and 8.5 on Mohs Scale of Hardness. That’s hard enough to be quite scratch resistant, but not scratch proof.   Because simulants can scratch they are better suited to special occasion rather than everyday wear.  Further if simulants are not looked after and cleaned they can become dull.

Still, Cubic Zirconia is an incredible value when you consider its cost.  Being lab-created It is always colorless and flawless.    To the average person, it’s hard to tell the difference between them and real diamonds.

A word of advice on buying faux diamonds

For shoppers buying a diamond simulant (Moissanite or some variety of cubic zirconia) who plan on replacing them with real diamonds in the future, we offer the following advice.

1.  Don’t buy too large a stone

Do not buy too large a stones up front. There are two reasons for this. First, smaller simulants look more realistic than larger ones. Second, you might not be able to afford a replacement of the same size in future. A good colourless 2 carat diamond simulant engagement ring might be US$100 – 200. In contrast a real diamond of the same size and color could cost US$20,000. You don’t want others to notice that you have “smaller rock” even if it is real.

2.  Go for a good cut simulants

With cubic zirconia and moissanite seek out the best cut.   Regardless of the material you start with, if the stones are not cut correctly, they will not have the brilliance and sparkle that maximizes their beauty.

With any diamond or diamond simulant, it is the cut of the stone that produces the brilliance and sparkle.   For round stones seek out a super ideal cut.   A Super Ideal Cut is a very tight set of proportions that will enable the diamond to return maximum and majority of the light – allowing it to essentially sparkle at its brightest.

Alternatively seek out rings with a brilliant cut and Hearts & Arrows (H&A) pattern.  This often indicates the stone has great optical symmetry. That means the way light reflects in the diamond is uniform from all directions because the facets were cut with great uniformity. If the cutter took the time to cut the stone with great optical symmetry, most likely all aspects of the cut were above average and you should expect a more beautiful appearance with regard to the cut.

Round cut diamond simulant with hearts and arrows pattern - Luxuria
Photo 8: Illustration of arrow pattern. According to IGS, Hearts and Arrows diamonds are precision-cut round diamonds. Because of their exact angles and symmetry, they show a hearts-and-arrows pattern when viewed through a special tool. Arrows are visible from the top of the diamond, and hearts are visible when the diamond is face-down.

While the cost of cutting a Hearts & Arrows CZ is more than a average CZ it is worthwhile.  There is a strong correlation between a diamond that exhibits hearts & arrows with a brilliant cut and a diamond that performs well in brilliance.

3.  Keep them clean!

After purchase remember to keep the stones clean.  This is because dirt, hand cream, grease, and soap scum will dull any type of material and diminish the beauty.

Often times diamond simulants appear to cloud and lose brilliance because they are not correctly cared for.   The more exposure to direct sunlight, chemicals, and abrasives a CZ has, the quicker it will lose its brightness and luster.

The tendency for CZ to take on a cloudy appearance is mostly due to the hardness of the stone. At a hardness rating of 8.5, CZ will eventually accumulate scratches plus it may absorb oils.  Also, if the back of the CZ stone becomes dirty under the setting it can lose a good amount of its luster and shine.

4.  Check out our article

Simulated diamond rings have become more popular as they become more realistic.  In this article we outline tips for buying a diamond simulant that will be perfect for you.   We cover topics like how to avoid rings that scream fake and matching the stone size and shape to fingers.

Tips buying a simulated diamond ring - Luxuria
Photo 9:   Luxuria® has written an article offering tips on buying a good diamond simulant ring.   Source:  Luxuria Diamonds

What Problems do Simulants Solve?

People buy simulant rings for all sorts of reasons.   Perhaps the most common reason is that diamond simulants look like diamonds but are cheap.  But what problems do simulants really solve?   Here are five big ones.

1.  Simulants reduce groom stress

Simulants are perfect as placeholder or proposal rings, temporary or otherwise.  They reduce groom stress.  When wanting to make a proposal guys simply have no idea which engagement ring to purchase and don’t want to risk spending thousands of dollars on a diamond engagement ring that she may hate.  It’s daunting.  Enter one raison d’être of engagement rings using diamond simulants.  Simply, they are a placeholder ring for her to wear until the “real” ring is found – ideally together, because only she knows what she wants.    Propose now.  Shop later!

Furthermore, what happens if she says “No”?  Sadly, it happens sometimes.  A Cubic Zirconia ring could be viewed as insurance against the unexpected.  If they say, ‘yes,’ they get a beautiful ring that didn’t run you into serious debt. If they say, ‘no,’ you don’t have to deal with a major financial loss at the same time you’re dealing with the shifting relationship.

No wonder Forbes Magazine calls out smart people as buying cubic zirconia rings.   Read our article on fake diamond rings.

2.  Simulants reduce travel stress

For all the fun of travel, keeping your valuables safe can be a constant source of stress. You already have to worry about your kids, your phone, wallet and tablet.  Why add your precious and sometimes irreplaceable engagement ring to the mix?   Wearing a faux ring with diamond simulants will guarantee the larger investment of a diamond engagement or wedding ring is not lost, damaged or stolen.  That’s not fun.  Check out our blog entitled “Going Abroad? Travel with One of These 8 Faux Diamond Rings for 2020”

3.  Simulants can complete your look

Its Friday night cocktails and with dress on and make up applied you are searching for a bit of bling to finish your look. For those who like to show off the beauty of their rings, a fake diamond ring acts as a great stand-in. Diamond simulants like cubic zirconia are a great alternative to traditional diamonds. Good quality simulants look indistinguishable from the real thing. Fake diamond rings can complete your look without emptying your wallet.  Hello beautiful. Seriously though, isn’t it time for a well-deserved treat for yourself?

Simulants from Luxuria Diamonds
Photo 10: There’s nothing like a bit of bling for a cocktail evening with friends. Seen here is a 4.6 ct. t.w. diamond simulant ring with a cushion cut central stone encircled by a scintillating halo of sparkling round cut white cubic zirconia diamond simulants which are also shoulder set. Source: Luxuria Diamonds

4.  Limiting diamond ring spending could be prudent

Let’s keep it real.   A good quality 1 carat diamond simulant ring with brilliant cut and H&A pattern might cost US$100.   An equivalent colorless (D color) mined diamond could easily cost US$10,000.   Instead of an expensive diamond – could the money be put to a better use?   The same money could contribute to a down payment on a home.   Some chose instead to upgrade their honeymoon.   Others chose to invest it in a Mutual Fund or retirement account.  Yet others start a college fund for a future child.   Initially limiting spending on a simulant ring opens up choices.  Those choices might be far better use of your money and improve your future.

And here’s some food for thought.    Studies show that more frugal couples actually have marriages that last longer. That’s the total opposite of what marketing messages lead us to believe.  Andrew Francis and Hugo Mialon, two economics professors from Emory University, surveyed more than 3,000 people in the study and found that the more expensive a wedding is, the sooner the couple is likely to divorce.  Meanwhile, couples who spent less than $1,000 on their wedding tend to have longer-lasting marriages.   Since wedding rings are a significant portion of the overall marriage costs, cheap wedding ring sets are possibly a good idea.

5.  Simulants might help keep creeps at bay!

Most women who want an engagement ring think of it as a symbol of their love and their commitment to their partner.  It’s a milestone, a marker, and a celebration. But it turns out some women are slipping on an engagement ring for a very different reason.  There’s a worrying new trend of women wearing fake engagement ring at work. It’s not as a way to proclaim their love and commitment.  Rather, it’s a way to deal with customers and coworkers who won’t leave them alone.  According to Brides Magazine it’shappening a lot.  According to the magazine wearing a fake engagement ring reduces harassment.  What a sad world!

Where to buy Diamond Simulants?

The good news is that diamond simulants are widely available online.   Many come with product warranty and free delivery.

Luxuria® Diamonds sells rings using natural diamond and diamond simulant.   Our product has been featured in the US media including USA Today, ABC6, Travel Weekly and various CNBC affiliates.

If you are interested to learn more click the below button to see our top selling diamond simulant engagement rings.

Finally, if you have any questions on the differences between natural diamonds, synthetics and simulants please contact us. A link to our contact page is below.