Diamond vs Moissanite vs Cubic Zirconia: What’s the Difference?

If you're shopping for an engagement ring or another piece of stone-set jewellery, you may find yourself comparing three popular options:

Diamond, moissanite and cubic zirconia.

All three can create a bright, sparkling look, but they aren't versions of the same stone.

They are different materials with different characteristics, price points and levels of durability.

So, which one should you choose?

That depends on what matters most to you: tradition, long-term durability, size, sparkle or budget.

Here’s a simple comparison.

Diamond vs Moissanite vs Cubic Zirconia at a Glance

The Gemological Institute of America rates diamond at 10 on the Mohs hardness scale, synthetic moissanite at approximately 9.25, and cubic zirconia at around 8.5. GIA also notes that moissanite produces more fire than diamond, while cubic zirconia has slightly more fire but less brilliance than diamond.

What Is a Diamond?

Diamond is its own gemstone, made primarily from carbon.

For generations, diamonds have been closely associated with engagement rings, weddings and significant jewellery purchases.

Part of their appeal comes from their combination of beauty and durability.

At 10 on the Mohs scale, diamond is the hardest natural material used in jewellery, making it particularly well suited to rings that are worn frequently.

Diamond jewellery can also vary enormously in price.

The value of a diamond is influenced by several characteristics, commonly including its cut, colour, clarity and carat weight.

This means two diamonds that look similar in size can have very different prices.

Why choose a diamond?

A diamond may suit you if you want a traditional engagement-ring stone, place importance on long-term durability or simply prefer the appearance and significance of a diamond.

It doesn't mean diamond is automatically the correct choice for everyone — especially if size or budget is a bigger priority.

What Is Moissanite?

Moissanite is a different gemstone from diamond.

The moissanite used in jewellery today is generally created in laboratories and is made from silicon carbide.

It has become a popular alternative for engagement rings because it combines significant durability with a bright appearance.

GIA gives synthetic moissanite a hardness of approximately 9.25, making it highly resistant to scratching and suitable for frequent wear.

Does Moissanite Look Like a Diamond?

It can look similar, particularly from a distance, but they don't sparkle in exactly the same way.

One of the most noticeable differences is fire — the coloured flashes produced as light passes through a stone.

Moissanite has more than twice the fire of diamond according to GIA, so it can produce stronger rainbow flashes, particularly under bright lighting.

Some people love that extra sparkle.

Others prefer the optical appearance of a diamond.

That makes this less about one stone being “better” and more about the look you personally prefer.

Why Choose Moissanite?

One of moissanite's biggest attractions is the combination of appearance, durability and price.

Because moissanite generally costs less than a comparable diamond, buyers may be able to choose a larger centre stone while remaining within their budget.

This can make it particularly appealing if you love the appearance of a larger solitaire engagement ring but don't necessarily want to allocate your entire jewellery budget to a diamond.

It is also significantly harder than cubic zirconia, making it a strong option for an engagement ring that will be worn regularly.

What Is Cubic Zirconia?

Cubic zirconia — commonly shortened to CZ — is a laboratory-created material frequently used as a diamond imitation.

It can be colourless and very clear, giving it an attractive diamond-like appearance at a much lower price.

Cubic zirconia measures around 8.5 on the Mohs scale. That still makes it relatively hard, but it is softer than both diamond and moissanite and therefore more susceptible to scratches over time.

Why Choose Cubic Zirconia?

The biggest advantage is affordability.

CZ makes it possible to achieve the appearance of a larger stone without the price associated with diamond.

This makes it particularly useful for buyers who want:

Affordable engagement or bridal jewellery, a larger stone within a limited budget, jewellery for occasional rather than constant wear, or simply an attractive piece without paying for a diamond.

Harris & D’Arcy, for example, carries a dedicated 9ct gold cubic zirconia bridal collection, alongside its diamond jewellery.

Does Cubic Zirconia Stay Sparkly?

CZ can look very bright when it is new, but because it is softer than diamond and moissanite, its surface can show wear more easily.

GIA notes that cubic zirconia is less hard than the other two stones and can change in appearance over time.

Regular gentle cleaning can help remove oils and product build-up, but scratches and physical wear cannot simply be cleaned away.

For a piece you intend to wear every day for many years, durability is therefore worth considering alongside the initial price.

Which Has the Most Sparkle?

This depends on what you mean by sparkle.

Diamond gives the classic balance of white brilliance and coloured fire that many people associate with engagement rings.

Moissanite produces more intense coloured flashes and can appear even more sparkly under certain lighting.

Cubic zirconia can also be very bright, particularly when new, although GIA describes it as having less brilliance than diamond.

The easiest way to understand the difference is to view the stones side by side.

Which Is Best for an Engagement Ring?

All three can be used for engagement rings.

The better question is:

What matters most to you?

If tradition, durability and owning a diamond are important, diamond may be the natural choice.

If you want excellent durability and a larger-looking stone for your budget, moissanite is worth considering.

If keeping the purchase affordable is the priority, cubic zirconia can give you a beautiful ring without the same financial commitment.

Harris & D’Arcy currently separates its engagement-ring range into diamond, moissanite and cubic zirconia options, making it possible to compare the different choices while shopping.

Don't Judge the Ring Only by the Centre Stone

The stone is important, but it isn't the whole ring.

Also consider the metal, setting, band design, ring size and how often the jewellery will be worn.

For example, a beautiful stone still needs a secure setting if the ring will be worn every day.

Your total budget should therefore consider the complete piece rather than simply focusing on getting the largest possible centre stone.

So, Which One Should You Buy?

There is no single option that suits every buyer.

Choose diamond if you value tradition, maximum hardness and the characteristics of a genuine diamond.

Choose moissanite if you want a very durable stone, strong sparkle and potentially more size for your budget.

Choose cubic zirconia if affordability is your main priority and you want an attractive diamond-like appearance without the higher cost.

And if you're still unsure, compare them in person.

The differences in sparkle and appearance are much easier to appreciate once you've actually seen the stones.

Diamond, moissanite or cubic zirconia? Explore Harris & D’Arcy’s engagement rings online, or visit us in store to compare your options and find the ring that suits your style and budget.

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You could also place three smaller links directly underneath:

Shop Diamond Rings | Shop Moissanite Rings | Shop Cubic Zirconia Rings