Moissanite vs Diamond: The Complete Guide for Australian Buyers
Moissanite vs Diamond: Which Stone Is Right for You?
Choosing between moissanite and diamond is one of the most important decisions you'll make when buying an engagement ring or fine jewellery. Both are stunning — but they differ significantly in origin, price, brilliance, and ethical footprint. This guide breaks it all down so you can shop with confidence.
What Is Moissanite?
Moissanite is a gemstone originally discovered in a meteor crater in 1893 by French chemist Henri Moissan. Natural moissanite is extraordinarily rare — almost all moissanite sold today is lab-created, making it a sustainable and conflict-free choice. Chemically, it is silicon carbide (SiC), giving it unique optical and physical properties that rival — and in some ways surpass — diamond.
Brilliance & Fire: How They Compare
One of the most striking differences between moissanite and diamond is how they interact with light.
- Refractive Index: Moissanite has a refractive index of 2.65–2.69, compared to diamond's 2.42. This means moissanite bends light more, producing exceptional brilliance.
- Fire (Dispersion): Moissanite has a dispersion rate of 0.104 vs diamond's 0.044 — more than double. This creates the rainbow flashes of colour moissanite is famous for.
- Verdict: If you love maximum sparkle, moissanite delivers. Some prefer diamond's more subtle, white-light brilliance — it comes down to personal taste.
Hardness & Durability
Both stones are exceptionally durable for everyday wear:
- Diamond: 10/10 on the Mohs hardness scale — the hardest natural substance on Earth.
- Moissanite: 9.25/10 on the Mohs scale — harder than sapphire, ruby, and all other gemstones except diamond.
For an engagement ring worn daily, moissanite is more than durable enough. It won't scratch, chip, or cloud over time with normal wear.
Price: The Biggest Difference
This is where moissanite truly shines as a value proposition:
- A 1-carat diamond of good quality (G colour, VS2 clarity) typically costs AUD $8,000–$15,000+.
- A comparable 1-carat moissanite costs AUD $500–$1,500 — roughly 80–90% less.
That price difference means you can choose a larger stone, a more intricate setting, or invest in 18k gold rather than gold-plated metal — all within the same budget.
Ethics & Sustainability
Lab-created moissanite is inherently conflict-free and has a significantly lower environmental impact than mined diamonds. If ethical sourcing matters to you — and for many Australian buyers it does — moissanite is the clear choice.
Diamonds can be certified conflict-free through the Kimberley Process, but the process has limitations. Lab-grown diamonds are also an ethical alternative, though they still carry a higher price tag than moissanite.
Colour
- Diamond: Graded D (colourless) to Z (light yellow/brown). Colourless diamonds (D–F) command premium prices.
- Moissanite: Available in colourless (DEF equivalent), near-colourless (GHI equivalent), and faint colour grades. Most modern moissanite is colourless and indistinguishable to the naked eye.
Can Jewellers Tell the Difference?
To the naked eye, a high-quality moissanite and a diamond look virtually identical. Gemologists can distinguish them using a thermal conductivity tester (moissanite conducts heat differently) or by examining the double refraction under magnification. For everyday wear and social settings, no one will know the difference.
Moissanite vs Diamond: Quick Comparison
| Feature | Moissanite | Diamond |
|---|---|---|
| Hardness (Mohs) | 9.25 | 10 |
| Refractive Index | 2.65–2.69 | 2.42 |
| Fire (Dispersion) | 0.104 | 0.044 |
| Price (1ct equivalent) | AUD $500–$1,500 | AUD $8,000–$15,000+ |
| Origin | Lab-created | Mined or lab-grown |
| Conflict-free | Always | Certified only |
| Durability | Excellent | Excellent |
Which Should You Choose?
Choose moissanite if you want maximum brilliance, exceptional value, and a conflict-free stone. It's ideal for engagement rings, pendants, and earrings where you want a large, eye-catching stone without the diamond price tag.
Choose diamond if tradition, resale value, or the prestige of a natural stone is important to you — and budget is not a constraint.
At Giulia's Secret, we specialise in premium moissanite set in 18k gold and 925 sterling silver — crafted to the same standard as fine diamond jewellery, at a fraction of the price. Explore our moissanite collection and find your perfect piece.
Frequently Asked Questions
Is moissanite a fake diamond?
No. Moissanite is a distinct gemstone with its own chemical composition (silicon carbide). It is not a diamond simulant like cubic zirconia — it has superior hardness, brilliance, and durability.
Does moissanite lose its sparkle over time?
No. Moissanite is extremely stable and will not cloud, fade, or lose brilliance with age. It can be cleaned at home with mild soap and water.
Is moissanite available in Australia?
Yes — Giulia's Secret ships moissanite jewellery across Australia with fast, tracked delivery.
What carat sizes does moissanite come in?
Moissanite is available in a wide range of sizes, from 0.5ct to 3ct and beyond. We stock popular sizes including 1ct, 1.5ct, 2ct, and 3ct equivalents in round, oval, cushion, and pear cuts.