Moissanite vs Diamond - Which Should You Choose?

Moissanite gives you more fire and a bigger-looking stone for far less money, but it isn't a diamond and doesn't behave like one on resale. A natural diamond carries tradition and, within limits, some resale value. A lab grown diamond sits between the two chemically a diamond, priced well below a mined one.

Moissanite vs Lab Grown vs Natural Diamond

What Is Moissanite, and What Is a Diamond?

Moissanite is silicon carbide. A diamond is pure carbon. That one difference explains almost everything else in this guide: the hardness, the way light behaves inside the stone, the price and the way each one is tested.

Moissanite was first identified in 1893 by the French chemist Henri Moissan, who found tiny crystals in meteorite debris from Arizona. Natural moissanite is far too rare to cut into jewellery, so every moissanite stone you can buy today has been grown in a laboratory.

How Is Moissanite Made?

Makers grow moissanite from silicon carbide seed crystals in a high-temperature furnace, a process that takes weeks. The resulting boule is sliced, graded for colour and cut into gems. Because the process is tightly controlled, the stones are consistent and traceable from furnace to finished ring. Moissanite is usually sold by diameter in millimetres rather than by carat, since it's a little lighter than a diamond of the same size.

How Are Natural and Lab Grown Diamonds Made?

Natural diamond formed deep in the earth's mantle between 1 and 3.5 billion years ago, and was carried up by volcanic activity. It's then mined, sorted, cut and polished.

A lab grown diamond is the same material, grown in weeks rather than eons, by one of two methods. High pressure, high temperature (HPHT) mimics the mantle. Chemical vapour deposition (CVD) builds the crystal layer by layer from a carbon-rich gas. Both produce real diamond, with the same crystal structure, hardness and optical properties as a mined stone. For more on that question, see our companion post, Are Lab Grown Diamonds Real Diamonds?.

Hardness and Durability

On the Mohs scale, diamond sits at 10, the top. Moissanite is 9.25. The gap matters more than the numbers suggest, because Mohs isn't a linear scale diamond is substantially harder than anything else on it. In practice, though, nothing you meet in daily life is hard enough to scratch either stone. Quartz dust, which is in ordinary household grit and sits at 7, won't mark moissanite.

Will Moissanite Chip or Scratch?

Scratching isn't a realistic concern. Chipping is a different matter, and it applies to every gemstone. Hardness measures resistance to scratching toughness is resistance to breaking. Diamond has cleavage directions and can chip if struck on a thin edge. Moissanite has no practical cleavage and good toughness, so a hard knock is unlikely to damage it. A well-made ring with protected edges, in either stone, will cope with years of daily wear.

Does Moissanite Get Cloudy?

Moissanite itself doesn't turn cloudy or change over time. What creates the impression of a cloudy stone is almost always a film of hand cream, soap residue or skin oil on the underside, which dulls the light. A soak in warm water with a drop of washing-up liquid, followed by a soft brush, brings the sparkle back. Diamond collects the same film and responds to the same cleaning.

Sparkle: Brilliance, Fire and How They Look in Person

Three things make a stone sparkle.

• Brilliance - White light returned to your eye.
• Scintillation - The flicker as the stone or the light moves.
• Fire - The splitting of light into spectral colours.

Moissanite has a refractive index of 2.65 to 2.69 against diamond's 2.42, and dispersion of 0.104 against 0.044. In plain terms, it throws back more light and more than twice as much colour. Diamond's sparkle is crisp, white and sharp. Moissanite's is livelier, with flashes of rainbow colour, especially under a single strong light source such as a spotlight or direct sun.

Not everyone likes that. Some buyers love the disco ball effect others find it reads as less natural than a diamond's cleaner white sparkle. It's a matter of taste, and worth testing in person if you can.

How Each Stone Photographs vs Real Life

In photographs, moissanite often looks more colourful than it does in the hand, because camera flash and studio lights produce the strongest rainbow flash. Diamonds can look flatter in images than they do on a finger. If you're comparing listings, look for photographs taken in daylight and, ideally, some video, which captures the movement that makes both stones work.

Which Looks More "Real"?

That depends on what you mean by real, and who's looking. A diamond looks like a diamond because most people have only ever seen diamonds. Across a room, a well-cut moissanite and a diamond look very similar to a non-expert. Up close, in strong light, moissanite's coloured flashes tend to give it away. In overcast British daylight and under indoor lighting, most wearers find the difference smaller than they expected.

Colour and Clarity

Diamond colour is graded from D (colourless) to Z (light yellow or brown). Most buyers choose between D and J; below that, a warm tint becomes visible. Clarity runs from Flawless to Included, and most buyers settle on something eye-clean, typically VS2 to SI1. 

Moissanite isn't graded on the diamond scale, but sellers often quote an equivalent range. Older moissanite sometimes had a faint yellow or green tint, particularly in larger sizes. Modern production has improved, and colourless grades are widely available. Look for the colour grade stated clearly on the listing, and judge it in daylight rather than under shop lighting.

Clarity in moissanite is usually high. The typical inclusions are fine needle-like lines, which differ from the crystals and feathers found in diamonds. A gemmologist can use them to identify the stone, but they rarely affect the look of a finished ring.

Lab grown diamonds are commonly available in higher colour and clarity grades than natural stones at the same price, since the grower controls the conditions. A lab-grown stone in F colour and VS1 clarity is easy to find; a natural diamond in the same grades costs considerably more.

Price: What £1,000, £2,000 and £5,000 Buys

Moissanite costs a fraction of a diamond of equivalent size, and lab grown diamond sits in between, though the gap between lab grown and natural keeps shifting as production costs fall. The figures below are indicative UK retail bands. Stone price is only part of a finished ring: metal, setting and any side stones all add to it.

One note on reading the table above. For natural diamond, per-carat prices rise with size, because large, well coloured rough is scarce. For lab-grown diamond and moissanite, per-carat prices usually fall slightly with size, because size isn't rare when it can be grown, so the large-stone premium largely disappears. That's why a 2 ct lab grown stone is often cheaper per carat than a 1 ct one.

At £1,000

A £1,000 budget puts a natural diamond at around 0.3 ct to 0.4 ct in a simple 9 ct gold solitaire, with modest colour and clarity grades. The same money in lab-grown diamond buys roughly a 1 ct to 1.3 ct round brilliant in a plain 9 ct gold setting. In moissanite it buys a ring with a stone of roughly 2 ct diamond-equivalent (about 8 mm) in a silver or 9 ct gold setting, often with meaningful design detail.

At £2,000

At this level, a natural diamond reaches roughly 0.5 ct to 0.6 ct with good colour and clarity, or around 0.75 ct in lower grades. A lab grown diamond stretches to roughly 2 ct to 2.5 ct in strong colour and clarity grades, set in 18 ct gold or platinum. In moissanite, £2,000 covers a 2.5 ct to 3 ct centre stone in a 9 ct or 18 ct gold setting, or a three-stone design with matching side stones.

At £5,000

A £5,000 budget buys a natural diamond of around 1 ct, depending on grade, usually set in platinum. A lab grown diamond at this price can reach 4 ct to 5 ct, with high colour and clarity. Moissanite stops scaling sensibly here. Stones above 3 ct are available, but a bigger stone isn't always better balanced on the hand, and the budget is often better spent on platinum or high-carat gold and a more considered design.

Ethics, Sourcing and Traceability

Moissanite and lab grown diamond involve no mining, and both can be traced back to the laboratory. Both use a lot of electricity, so the carbon footprint depends on where and how the factory is powered. Ask the seller whether the maker has published energy data.

Natural diamonds carry the heavier history. The Kimberley Process was set up in 2003 to stop conflict diamonds entering the market, but it has well known gaps it covers violence by rebel groups, not labour conditions or environmental damage. Many mined diamonds come from well regulated operations, and the industry supports livelihoods in several countries. Others don't meet that standard.

For buyers who want a diamond with a short and clear supply chain, lab grown is the easiest option. For buyers who want to avoid diamonds entirely, moissanite is the simplest.

Resale and Long Term Value

• Natural diamond - It won't hold its retail price. Retail markups mean that if you sell a ring back to a jeweller, you should expect to be offered a fraction of what you paid. Larger, well certificated stones in high colour and clarity grades hold their value better than small commercial ones. A diamond is a store of sentimental value more than a financial investment, though it's the only one of the three with a meaningful second-hand market.
• Lab grown diamond - A much weaker resale position. Prices have fallen steadily as production has scaled, and that trend may continue. A stone bought today may be worth noticeably less in five years. You're paying for a real diamond to wear, not an asset to sell.
• Moissanite - Almost no resale market. It's priced as a gemstone to be worn, and the secondary market barely exists. If you buy it, treat the money as spent on something you'll keep.

Resale should carry little weight in your decision, unless you're specifically buying a large, certificated natural stone.

How to Tell Moissanite and Diamond Apart

You can often tell them apart with a bit of care, though it takes a loupe and some experience. This is the sequence a jeweller would follow:

1. Look at the sparkle - Hold the stone under a single bright light. Moissanite throws out strong rainbow flashes; diamond shows more white and grey.
2. Check the facet edges - With a 10x loupe, look through the table at the back facets. In moissanite they appear doubled, because the stone is doubly refractive. In diamond they look single and crisp.
3. Look for inclusions - Fine parallel needles suggest moissanite. Natural diamonds more often show crystals, feathers or clouds.
4. Check the girdle - Larger certificated stones are often laser-inscribed with a report number, which you can match to the grading report.
5. Use an electrical conductivity tester - A moissanite specific tester usually gives a clear reading.
6. Ask for a grading report - For a stone you're paying a lot for, an independent report from a recognised laboratory is the only firm answer.

Can a Jeweller Tell the Difference?

Yes, with the right tools. An experienced jeweller will spot moissanite with a loupe in a few seconds, by the doubling of the back facets, the pattern of inclusions and the colour flash. Without magnification it takes a practised eye, and plenty of people in the trade won't commit to an answer across a counter.

Does Moissanite Pass a Diamond Tester?

Often it does, which surprises people. Standard handheld diamond testers measure thermal conductivity, and moissanite conducts heat almost as well as diamond, so many testers read it as a diamond. Testers that measure electrical conductivity, or that are calibrated for moissanite, separate the two in most cases. Treat a basic tester reading with caution.

Which Settings Flatter Each Stone?

Moissanite's fire shows best in settings that let light in from the sides and below. A raised four-claw or six-claw solitaire does this well, as does a hidden halo on a slim band. Because the coloured flashes are strong, a plain setting often looks better than a heavily decorated one that competes with the stone.

Diamond, lab grown or natural, works in almost any setting. A classic solitaire shows the stone at its best, and a pavé band or a halo adds sparkle without hiding the centre. Vintage and art deco designs, with milgrain edging and step-cut side stones, suit diamond particularly well.

Metal matters too. In yellow or rose gold, a lower colour stone of any type can look warmer and less noticeable; white gold or platinum keeps colourless stones looking colourless. Bezel settings suit active wearers and work with all three stones, with the trade-off that they let in less light.

Warranty, Care and Cleaning

Both stones need very little maintenance. Clean them at home every couple of weeks in warm water with a drop of mild washing-up liquid, using a soft toothbrush, then rinse and dry with a lint-free cloth. Avoid hand cream and cosmetics while wearing the ring, and take it off for the gym, gardening and swimming. Chlorine won't harm the stones but can affect the metal.

Have the setting checked once a year, so a loose claw is caught before a stone is lost. That matters more than the choice of stone. Our diamond care guide covers cleaning, storage and what to avoid in more detail.

Check the warranty terms for each ring you consider, along with the returns policy and whether the stone comes with an independent grading report. Warranty and returns terms are shown on each product page.

So Which Should You Choose?

• Budget-first - If you have a firm ceiling and want the most for it, moissanite gives you the most stone for your money. You get a larger, livelier gem, and the savings can go into the metal or the design. Browse our moissanite jewellery.
• Size-first - If the goal is a big stone on the hand, moissanite and lab-grown diamond both do this better than natural diamond at the same price. Choose moissanite for maximum colourful sparkle, and lab grown if you want diamond hardness and a whiter flash.
• Tradition-first - If you want a mined stone, perhaps because it has family meaning, or because you want a graded certificate and the best chance of holding some value, buy natural. Accept that you'll pay more for less size. Our diamond engagement rings are a good place to compare grades.
• Ethics-first - If avoiding mining is the priority, moissanite and lab-grown diamond are both options, and you should ask each maker about energy sourcing. If you prefer a natural stone, choose one with clear provenance and documentation, and ask for it before you buy. Start with lab grown diamond or moissanite jewellery.
• Want a diamond, but not the price - Lab grown is the answer for most people here. It's real diamond, graded in the same way, at a considerably lower cost than a mined one. Accept that resale is weak, and enjoy the size and quality you get.