Lab-Grown Diamond vs Moissanite vs Cubic Zirconia: What's the Difference?

Lay three stones side by side on black velvet and, in a photograph, they could almost be triplets: clear, bright, faceted, glinting. Turn them in daylight and the differences begin to speak. If you're shopping for an affordable engagement ring, you'll come across these three again and again: lab-grown diamond, moissanite and cubic zirconia. When it comes to lab-grown diamond vs moissanite, they can look similar in photos, but they are very different materials. Here's how to tell them apart and choose wisely.

Lab-grown diamond vs moissanite: the short answer

• Lab-grown diamond is a real diamond, chemically and physically identical to a mined diamond.
• Moissanite is silicon carbide, a different gemstone that looks diamond-like but sparkles differently.
• Cubic zirconia (CZ) is an inexpensive simulant that scratches and clouds over time.

In other words, only one of the three is a diamond. The other two are alternatives that imitate a diamond's look to different degrees, and that distinction matters most for a ring you intend to wear every day for the rest of your life.

Side-by-side comparison

Here is how the three stones compare on the qualities that matter for an engagement ring.

Lab-grown diamond: the real thing, grown above ground

A lab-grown diamond is the real thing, just grown above ground rather than mined. It is made of carbon arranged in the same crystal structure as a natural diamond, grown using one of two established methods: HPHT (high pressure, high temperature), which recreates the conditions deep inside the earth, or CVD (chemical vapor deposition), which builds the crystal layer by layer. The result has the hardness, brilliance and fire of any diamond and comes with an independent grading report.

For anyone who wants a diamond at a more accessible price, it's the natural choice. Every LUXEIGA lab-grown diamond is graded by an independent lab, IGI or GIA, and the certificate is included with your ring. See lab-grown vs mined diamonds, and if you want to know how those reports differ, read IGI vs GIA lab diamond certificates.

A lab-grown diamond doesn't imitate a diamond. It is one, simply grown in a different place.

Moissanite: a beautiful gemstone in its own right

Moissanite is a beautiful, durable gemstone in its own right, and very hard. At about 9.25 on the Mohs scale, it sits just below diamond and well above most other gemstones, so it stands up well to everyday wear.

Its sparkle is different from a diamond's: it throws more colorful, rainbow-like flashes, which some people love and others find less classic. The effect is most noticeable in bright sunlight and in larger stones, where moissanite can take on a lively, almost disco-ball brilliance. A diamond's light tends to read as crisper and whiter, balanced by flashes of color rather than dominated by them.

It is not a diamond, and it doesn't hold value like one. That doesn't make it a poor choice; it simply makes it a different one. If you love its particular glow and it suits your budget, it can be a lovely stone. If your heart is set on a diamond, moissanite is a substitute rather than an equivalent.

Cubic zirconia: fine for fashion, not for forever

Cubic zirconia is inexpensive and fine for fashion jewelry, but it is much softer than diamond. Over years of daily wear it scratches and loses its sparkle, so it isn't a good choice for a ring worn every day for a lifetime. Think of it as a stone for a statement pair of earrings or a costume piece, rather than for the ring that will mark your engagement, your wedding day and every year after.

Lab-grown diamond vs moissanite: which should you choose for an engagement ring?

If you want a real diamond that will last forever and look like the classic engagement ring, choose lab-grown. Because lab-grown diamonds are so much more affordable than mined ones, the price gap with moissanite is often smaller than people expect. See real numbers in how much a lab-grown diamond ring costs.

A simple way to decide is to ask yourselves three questions:

• Does it matter that it is a diamond? If yes, the choice is already made: lab-grown.
• Which sparkle do you prefer? Classic white brilliance points to diamond; bolder rainbow fire may point to moissanite.
• Will it be worn every day for decades? Both diamond and moissanite are durable enough; cubic zirconia is not.

Choose the stone you will still love on an ordinary Tuesday, twenty years from now.

See the difference for yourself

Photographs flatten what the eye notices instantly. Book a free video consultation and we'll show you lab-grown diamonds on camera in natural light, or design your lab-grown diamond ring in 3D now. Every LUXEIGA ring is handcrafted to order, delivered free with insured, tracked shipping to the UK and USA, and comes with 30-day returns and a free resize.

Frequently asked questions

Is moissanite a lab-grown diamond?

No. Moissanite is silicon carbide, a different gemstone. A lab-grown diamond is pure carbon and is a real diamond, chemically and physically identical to a mined one.

Which is harder, lab-grown diamond or moissanite?

Diamond, at 10 on the Mohs scale. Moissanite is about 9.25, which is still very hard and durable for everyday wear.

Can you tell moissanite from diamond by looking at it?

Often, yes, especially in sunlight. Moissanite throws stronger, more colorful rainbow flashes, while a diamond shows a crisper, more classic balance of white brilliance and fire.

Is cubic zirconia good enough for an engagement ring?

Not for everyday, lifelong wear. At about 8 to 8.5 on the Mohs scale, it scratches and clouds over time and loses its sparkle.