The difference between a natural, lab and moissanite

A natural diamond is pure carbon that formed deep in the earth over a billion years under heat and pressure, then was mined. A lab-grown diamond is pure carbon that was grown in a chamber over a few weeks under controlled heat and pressure. They are chemically and physically the same material; the only difference is where they grew. Both are rated 10 on the Mohs hardness scale and both grade identically on the 4Cs.

A moissanite is a completely different stone. It is silicon carbide rather than carbon, rated 9.25 on the Mohs hardness scale (still very hard, but not diamond-hard), and visually resembles a diamond but with more rainbow fire because of its higher refractive index and dispersion. Moissanite is almost always lab-grown for jewellery, since natural moissanite exists only in trace amounts in meteorites.

A quick three-way summary by material, hardness, and AUD price for a 1 carat round brilliant equivalent:

• Natural diamond: carbon, Mohs 10, $5,000 to $12,000 AUD for the loose stone
• Lab-grown diamond: carbon, Mohs 10, $800 to $1,800 AUD for the loose stone
• Moissanite: silicon carbide, Mohs 9.25, $200 to $600 AUD for the loose stone

For most engagement ring buyers in 2026, the practical choice is between lab-grown diamond and moissanite. Natural is still chosen by buyers who want the geological story or specific certification provenance, but it is no longer the default.

Functionally, no. Natural moissanite does exist (it was first discovered in 1893 by Henri Moissan inside a meteorite crater in Arizona), but it is so rare that essentially all moissanite used in jewellery today is lab-grown silicon carbide. When you buy a moissanite engagement ring, you are buying a lab-created stone.

That is not a downside, just a fact about the supply. The lab-grown moissanite is the same material as the natural version (silicon carbide). The growing process produces consistent, high-quality stones that are nearly indistinguishable from natural moissanite. It is essentially the same situation as lab-grown diamonds in that respect.

So if a jeweller describes moissanite as a "natural alternative to diamond", that is marketing language. Moissanite in jewellery is a lab-grown gemstone. It is real, it is durable, it is beautiful, but it is made rather than mined.

No. Moissanite is a different gemstone, made of silicon carbide rather than carbon. It looks similar to a diamond from across a room, and the average person would not be able to tell them apart side by side, but it is chemically distinct.

The visible differences when you compare moissanite and diamond directly:

• Sparkle: moissanite throws more rainbow fire because its dispersion (0.104) is more than double that of a diamond (0.044). Diamond sparkles with whiter, cleaner flashes.
• Brilliance: moissanite has a slightly higher refractive index (2.65 vs diamond's 2.42), so it returns marginally more light overall.
• Hardness: diamond is 10 on the Mohs scale, moissanite is 9.25. Both are hard enough for daily wear but diamond scratches less.
• Density: moissanite weighs less than diamond per millimetre, so the carat weight number on a moissanite does not match the physical size of a diamond at the same weight. Moissanite is sold by mm size more than by carat weight.

For more on the sparkle comparison specifically, see our education guide on moissanite vs diamond.

Yes. A lab-grown diamond is real, certifiable, gemmologically identical to a mined diamond. Both are pure crystallised carbon arranged in the same crystal lattice, both grade identically on the 4Cs (cut, colour, clarity, carat), and both are graded by the same labs (GIA, IGI) using the same equipment.

A trained gemmologist cannot tell a lab-grown diamond apart from a mined diamond by looking at it under a loupe. The only way to distinguish them is with specialised equipment that detects subtle differences in trace elements (mined diamonds usually contain tiny amounts of nitrogen, lab-grown diamonds usually do not). Our at-home diamond testing guide explains why simple tests cannot separate the two.

The single material difference is origin. A lab-grown diamond was grown in a chamber over a few weeks. A mined diamond formed in the earth over a billion years. Whether that origin matters is the only personal question.

Rough 2026 AUD price bands for a 1 carat round brilliant equivalent at decent quality (G colour, VS2 clarity, excellent cut):

• 1 carat natural diamond: $5,000 to $9,000 loose, $6,500 to $12,000 set
• 1 carat lab-grown diamond: $800 to $1,500 loose, $1,800 to $3,500 set
• 1 carat moissanite (mm-equivalent size): $200 to $500 loose, $1,000 to $2,000 set

At 2 carats the gap widens:

• 2 carat natural diamond: $20,000 to $40,000 loose, $22,000 to $45,000 set
• 2 carat lab-grown diamond: $2,500 to $5,000 loose, $4,000 to $7,500 set
• 2 carat moissanite equivalent: $400 to $900 loose, $1,800 to $3,000 set

The reason the gap widens with carat is that natural diamond prices scale with rarity (large stones are much rarer than small ones). Lab-grown diamond prices scale more linearly because the growing process is the same regardless of size. Moissanite prices scale very slowly because the material is essentially limitless.

Diamond is harder. The Mohs hardness scale is logarithmic, not linear, so a 10 (diamond) is meaningfully harder than a 9.25 (moissanite) even though the numbers look close. In practical terms:

• Diamond (Mohs 10): essentially does not scratch under any normal jewellery condition
• Moissanite (Mohs 9.25): very scratch-resistant, but can be scratched by a diamond and by some industrial materials
• Sapphire or ruby (Mohs 9): scratch-resistant for most wear, but more easily marked than moissanite
• Quartz (Mohs 7): scratches with sand and dust, not suitable for daily-wear centre stones

For daily wear on an engagement ring, both diamond and moissanite are durable enough that you will not see surface scratches on the stone in your lifetime. The differences only matter if you regularly wear the ring through industrial conditions or sandblasting.

Moissanite has more visible sparkle, especially in bright direct light, because its dispersion (the property that creates rainbow flashes) is more than twice that of diamond. In sunlight or under spotlights, a moissanite throws strong colour and reads as visibly more "showy" than a diamond of the same size.

Diamond sparkle is whiter and more contained. Light enters the stone, bounces around inside, and returns as a mix of bright white flashes and scattered colour. Diamond is the more classic, more familiar look. Moissanite is the more energetic, more colourful look.

Neither is "better". The choice is taste. People who like the traditional diamond look usually pick diamond; people who want maximum visual impact for the budget often pick moissanite.

The honest decision frame:

Pick a lab-grown diamond if:

• You want it to be a diamond (chemically, gemmologically, and on paper)
• The traditional diamond sparkle pattern matters to you
• You want a certified stone with a GIA or IGI report
• The cost gap between lab-grown and moissanite is acceptable for what you gain in "diamond identity"

Pick a moissanite if:

• You want the most visual size and sparkle for the lowest cost
• You genuinely do not need it to be a diamond
• You like the more energetic, colourful sparkle pattern
• You want to spend the saving on the setting, on the wedding, or on something else

For most buyers in 2026, lab-grown diamond is the more common choice because the price gap from a 1 carat moissanite to a 1 carat lab-grown diamond is only $500 to $1,000 AUD, and a lot of buyers value the diamond identity at that price difference. For 2 carats and above, where the gap widens to $2,000+, moissanite becomes a more compelling case if budget is tight. The close-up appearance question is covered separately in does moissanite look fake.

Lab-grown for almost every reason except one. Lab-grown diamonds:

• Are chemically and visually identical to mined diamonds
• Grade the same on the 4Cs
• Cost roughly 15 to 25 percent of mined diamonds for the same specifications
• Have a clearer ethical and environmental story (no mining, no human rights concerns, lower carbon footprint)
• Are not distinguishable from mined diamonds without lab equipment

Mined diamonds make sense for buyers who:

• Specifically want the geological provenance (the stone formed over a billion years)
• Are buying for a known long-term resale market that prefers mined diamonds
• Are buying a stone with specific certified mined provenance (a Canadian-origin diamond, for example)
• Have a strong personal or family preference for mined origin

For a fuller treatment of this comparison, see our education guide on lab-grown vs natural diamonds. For value specifically, our are lab-grown diamonds worth it guide goes deeper.

A quick decision frame:

• Origin matters most: natural diamond
• You want a diamond and the most stone for the budget: lab-grown diamond (the most common modern choice)
• You want maximum sparkle and visual size for the least money: moissanite
• You want exceptional durability: any of the three; diamond is marginally harder but all are fine for daily wear

Most of our buyers at Lily Dia choose lab-grown diamond, which is also our specialty. Some choose moissanite for the value. Very few choose mined diamond now that lab-grown is widely understood.

View our collection of lab-grown diamond engagement rings to see what the most popular modern choice looks like in real designs.

Thanks for reading,
Jared and Brie