What Is Moissanite?
The stone, the science, the comparisons, and the questions South African buyers actually ask — answered plainly.
Moissanite is a gemstone made of silicon carbide, first discovered in 1893 in a meteorite crater. It is not a diamond. It is its own material with a higher refractive index than diamond (2.65–2.69 vs 2.42), a hardness of 9.25 on the Mohs scale, and a cost 70 to 85% lower than a mined diamond of the same visual size. All moissanite used in jewellery is lab-created. Moissanite in South Africa is available from Moissanite by Design as a custom ring from R8,000.
In 1893, French chemist Henri Moissan was examining rock samples from a meteorite crater in the Arizona desert when he found something he could not identify. The crystals were harder than anything he had seen outside diamond. They sparkled differently. They were not carbon. He had found silicon carbide, a compound so rare in nature that it had never been formally catalogued as a gemstone. It was named moissanite in his honour, and for most of the following century it remained a geological curiosity with no commercial application.
That changed in 1998, when a company called Charles & Colvard developed a process to grow silicon carbide crystals in a laboratory at gem quality and introduced moissanite to the jewellery market. The patents expired in 2018, and today moissanite is produced by multiple manufacturers worldwide. Every moissanite stone in a ring, earring, or necklace is lab-created. There is no commercially viable source of natural moissanite in the sizes needed for jewellery.
What Moissan found in that crater, and what is now made in laboratories, is one of the most optically remarkable gemstones available. Understanding why requires looking at three specific properties: hardness, refractive index, and dispersion. Everything else about moissanite follows from those three numbers.
(diamond is 10)
(diamond is 2.42)
(diamond is 0.044)
The Science Behind the Stone
Hardness
Hardness in gemology measures resistance to scratching, not resistance to breaking. The Mohs scale runs from 1 to 10, with diamond at 10 as the upper limit. Moissanite scores 9.25. Sapphire and ruby both score 9 and are universally considered appropriate for daily wear in fine jewellery. Moissanite is harder than both.
In practical terms, this means moissanite will not be scratched by anything in ordinary daily life. The surfaces you encounter every day, stone countertops, metal surfaces, other jewellery, cleaning products, register below 9 on the Mohs scale. Only diamond can scratch moissanite. A moissanite ring worn every day for forty years will have the same sharp facet edges and the same surface polish as the day it was made.
Refractive index and brilliance
The refractive index measures how much a material bends light as it passes through the stone. The higher the index, the more dramatically light is redirected back toward the viewer. Diamond's refractive index is 2.42, which is already exceptionally high by gemstone standards. Moissanite sits between 2.65 and 2.69, higher than diamond.
The result is that moissanite is objectively more brilliant than diamond in the technical sense of that word. More light is returned to the eye, more intensely. This is not a matter of opinion or marketing. It is physics.
Dispersion and fire
Dispersion is a separate property from brilliance. Where brilliance refers to white light reflected back from a stone, dispersion refers to how a stone breaks white light into its spectral colours, the rainbow flashes jewellers call fire. Diamond has a dispersion rate of 0.044. Moissanite has a dispersion rate of 0.104, which is 2.4 times higher.
This means moissanite produces significantly more coloured light flashes than diamond. In bright lighting, particularly direct sunlight or under spotlights, this creates a vivid, multi-coloured sparkle that some buyers love and others find too intense. In softer indoor lighting, the difference is less pronounced. Whether you prefer moissanite's fire or diamond's cooler white brilliance is a matter of personal preference. Both are genuinely beautiful. What matters is that you know which you are choosing.
"Moissanite is not trying to be a diamond. It has better fire than diamond, comparable brilliance, and a fraction of the cost. Once you understand what it actually is, the choice becomes very clear."
Lorna, Founder and Master Jeweller, Moissanite by DesignChoosing Your Stone
Moissanite Colour Grades Explained
Early moissanite, produced in the late 1990s and early 2000s, had a noticeable yellowish or greenish tint. This is where most of the "moissanite looks fake" criticism originates. Modern colourless moissanite produced since approximately 2015 has none of that tint, and is visually equivalent to a D–F coloured diamond in normal lighting conditions.
Equivalent to D–F on the diamond colour scale. No visible warmth in any metal colour. The standard recommendation for engagement rings, particularly in white gold or platinum settings where warmth would be most visible.
Equivalent to G–I on the diamond scale. Minimal warmth visible only under close scrutiny or in certain lighting. Entirely appropriate for yellow gold or rose gold settings where a warmer tone is expected and complementary.
Equivalent to J–K. A slight warmth visible to the naked eye in direct light. Not recommended for engagement rings by Moissanite by Design. We use colourless or near-colourless stones as standard on every ring we produce.
Every custom ring from Moissanite by Design uses colourless or near-colourless moissanite. Stone grade is confirmed and documented during the design stage and included in the ring certificate that ships with every piece.
The Comparison
Moissanite vs Diamond vs Lab Diamond
The three questions South African buyers ask most often during a consultation at Moissanite by Design are: is moissanite a real gemstone, can you tell the difference, and why is it so much cheaper. For South African buyers comparing moissanite, lab diamond, and mined diamond, the price difference is the most significant factor. The table below answers all three, along with everything else that matters when making this decision. For a deeper breakdown of costs and the custom process, see the custom engagement rings guide.
| Property | Moissanite | Lab Diamond | Mined Diamond |
|---|---|---|---|
| Chemical composition | Silicon carbide (SiC) | Carbon (identical to mined) | Carbon |
| Mohs hardness | 9.25 | 10 | 10 |
| Refractive index | 2.65 – 2.69 | 2.42 | 2.42 |
| Dispersion (fire) | 0.104 | 0.044 | 0.044 |
| Price per carat (SA retail) | R3,000 – R6,000 | R10,000 – R18,000 | R35,000 – R80,000+ |
| Origin | Lab-created | Lab-created | Mined |
| Conflict-free | Always | Always | Not guaranteed |
| Graded on 4C scale | No | Yes | Yes |
| Resale value | Low | Low to moderate | Lower than most assume |
| Distinguishable by eye | No | No | No |
| SA retail prices indicative. Updated May 2026. Custom ring prices vary by design and metal. | |||
Why moissanite costs less
Moissanite is not cheap because it is inferior. It is less expensive because it is grown in a laboratory at scale, without the extraction costs, supply chain markups, cartel pricing structures, or retail margins that inflate diamond prices. The stone itself is physically harder than sapphire, more brilliant than diamond, and entirely conflict-free. The price gap reflects economics, not quality.
Moissanite vs lab-grown diamond: which to choose
This is the question Moissanite by Design clients ask most often. Lab-grown diamonds are chemically identical to mined diamonds and carry a 4C grading certificate. If that certificate matters to you or your partner, a lab-grown diamond makes sense. If you want the largest, most brilliant stone your budget can deliver in a fully custom design, moissanite delivers a better result for less money. The right answer depends entirely on what you are optimising for. The free consultation is where that conversation happens.
Setting the Record Straight
Five Things People Get Wrong About Moissanite
Most of the misconceptions about moissanite come from outdated information, from jewellers with a financial interest in selling diamonds, or from people who have only seen low-grade stones from a decade ago. Here is what is actually true.
Moissanite is not a diamond simulant or a fake anything. It is a distinct gemstone with its own chemical composition (silicon carbide), its own optical properties, and its own identity in gemology. Calling moissanite a fake diamond is like calling a sapphire a fake diamond. They are simply different stones.
To the naked eye, in everyday wear and in photographs, modern colourless moissanite is visually indistinguishable from a high-quality diamond. A trained gemologist using a UV loupe or a moissanite-specific tester can identify the difference. A standard diamond tester will often give a false diamond reading for moissanite because their thermal conductivity is similar. Your partner's friends, your family, and anyone seeing the ring in normal circumstances will not know unless you tell them.
There is no documented evidence of moissanite changing its optical properties over time. Its 9.25 hardness means it resists scratching from every surface it encounters in ordinary life. It does not cloud, it does not tarnish, and it does not need any special maintenance beyond the same routine cleaning you would give any fine jewellery. A moissanite ring will look identical in forty years.
Moissanite is a choice, not a compromise. Many buyers who could comfortably afford a mined diamond choose moissanite specifically because they prefer its fire, because they object to diamond mining on ethical grounds, or because they would rather spend the money elsewhere. The stone's price does not determine its meaning. The ring's meaning comes from the relationship it represents.
With a Mohs hardness of 9.25, moissanite is the second hardest gemstone used in jewellery. It is harder than sapphire, harder than ruby, and harder than every other gemstone except diamond. An engagement ring is worn every day for life. Moissanite handles that wear with no deterioration whatsoever. This is not theoretical. Moissanite by Design has clients who have worn their rings daily for years with no change in appearance.
The Decision
Is Moissanite Right for You?
Moissanite is the right choice if you want the largest, most brilliant stone your budget allows. If you want a ring designed entirely around your partner's taste rather than constrained by the cost of the stone. If you want a conflict-free, lab-created gemstone with documented provenance. If you want to invest the money you save in your life together rather than in retail margin.
Moissanite may not be the right choice if a 4C diamond grading certificate matters specifically to your partner. If the cultural significance of diamond as a material is important to the person wearing the ring. Or if you are buying a ring as a financial asset, though it is worth noting that no engagement ring, including a mined diamond, is a sound financial investment by any conventional measure.
The honest answer is that for most South African couples buying a custom engagement ring in 2026, moissanite delivers a better visual result, a more personalised design process, and a significantly more reasonable price than any comparable option. That is why Moissanite by Design is South Africa's dedicated moissanite custom ring studio.
If you want to see exactly what moissanite looks like in a ring built to your specification, the starting point is the free consultation. No obligation, no pressure, and the design process starts the moment you do. You can also browse the full engagement ring collection to see what is possible, or read the complete custom engagement ring guide for a full breakdown of costs, the process, and what to look for in a jeweller.
Questions and Answers
What People Ask About Moissanite
What exactly is moissanite made of?
Is moissanite the same as a diamond?
How hard is moissanite compared to diamond?
Does moissanite sparkle more than diamond?
Can you tell moissanite from diamond with the naked eye?
What colour grade should I choose for a moissanite engagement ring?
Is moissanite a good choice for an engagement ring in South Africa?
How much does a moissanite ring cost in South Africa?
Does moissanite last forever?
Is moissanite conflict-free?
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