What Lab Grown Diamond Engagement Rings Cost in Australia

Our lab grown diamond designs start at AU$1,350. That is a complete ring, made in our Southbank studio, with an IGI certified centre stone.

What that number does not tell you is why the next ring up the range costs three times as much, or why two rings both described as "one carat, colourless, eye clean" can differ by thousands. Price lists get out of date within months in this category, and any article that gives you a table of exact prices per carat is either stale or making it up. What does not go out of date is the order in which the variables move the number.

That order is: carat, then cut, then colour, then clarity, then shape, then setting and metal. Understand those six and you can price any ring you see, anywhere, and work out whether it is fair.

Carat, and why the jumps are not smooth

Carat is weight, not size. One carat is 0.2 grams. A one carat round brilliant measures about 6.5mm across the top.

Price per carat does not rise in a straight line. It steps. A 1.00 carat stone costs meaningfully more per carat than a 0.90 carat stone, even though the difference in diameter is about a fifth of a millimetre and nobody has ever detected it on a hand. The same jump happens at 1.50, at 2.00, at 3.00.

The reason is demand, not rarity, because in a grown stone there is no rarity. Buyers ask for round numbers. Cutters know this and will sacrifice proportions to keep a stone above a threshold, which means well cut stones just below a threshold are relatively scarce and well cut stones just above it are relatively abundant and relatively expensive.

The practical move: shop just under the round numbers. A 1.90 carat stone next to a 2.00 carat stone is a 1.5 per cent difference in diameter. You will not see it. Your budget will.

If you are not sure what different carat weights actually look like on a hand, that is worth settling before you set a budget, because most people overestimate what they need. The quickest way to calibrate is to look at real stones at real sizes in the lab grown diamond engagement rings collection.

Cut, the one to protect

Cut is the only one of the four Cs that is about workmanship rather than the stone itself, and it is the one that determines whether the diamond looks alive.

A poorly cut diamond leaks light out the bottom. It can be flawless and colourless and still look dull, because the proportions are wrong: the pavilion is too deep or too shallow, the table is too large, the facets do not line up. A well cut stone returns light back up through the table to your eye.

For round brilliants, IGI issues an actual cut grade, and Excellent is the floor I would work to. It is the single best use of money in the whole specification, because it affects every second you look at the ring.

For every other shape, oval, pear, emerald, radiant, cushion, marquise, there is no official cut grade anywhere in the industry. You get polish and symmetry grades, which are related but not the same thing. This means fancy shapes have to be judged by eye and by measurement: length to width ratio, depth percentage, and for ovals and pears whether there is a bowtie, the dark bar across the centre that appears when the pavilion facets are cut wrong. Some bowtie is normal. A heavy one is a badly cut stone and no certificate will tell you about it.

This is the single biggest reason to buy a fancy shape from someone who looks at the actual stone rather than the report.

Colour

Graded D through Z. D, E and F are colourless. G, H, I and J are near colourless. Below that, warmth becomes visible face-up.

The price steps at each letter, and the steps between D and G are steeper than the visible difference justifies. In a mounted ring, viewed face-up, most people cannot separate a D from a G without a comparison stone next to it under controlled lighting.

The metal changes the calculation entirely. In platinum or white gold, a warmer stone has cool white metal right beside it and any tint shows more. In yellow or rose gold, the metal is warmer than the stone, so a G or H reads as bright white by contrast and paying for a D is close to pouring money away.

Lab grown stones are also sold in fancy colours, yellows, pinks and blues, which are priced on a completely different logic and are outside the scope of this page.

Clarity

Graded from Flawless down through VVS, VS, SI and I, based on inclusions visible under 10x magnification.

The only question that matters for a ring you will wear is whether the stone is eye clean at normal viewing distance. A VS2 with a small inclusion tucked under a crown facet and an IF stone look identical on a hand, and there is a lot of money between them.

Where I would not economise: any inclusion near the girdle or at a point of the stone, because that is a structural risk when it is being set and when it is knocked later. A grader will call it a minor clarity characteristic. A setter will call it a problem.

Shape, and why ovals cost more per carat

Round is the volume shape. Everything else is a fancy shape, and fancy shapes do not price the way people expect.

Elongated shapes, oval, pear, marquise, elongated radiant and cushion, spread. They present a larger face-up area for the same weight, because more of the stone is in the top and less is buried in the pavilion. A 1.50 carat oval can look like a 1.75 carat round on a hand.

You would expect that to make them cheaper per carat, and for a long time it did. Right now it does not, for two reasons.

The first is demand. Ovals and elongated cushions have been the most requested shapes for several years and pricing follows demand.

The second is selection. Because there is no cut grade for fancy shapes, the proportion of production that is actually well cut, good ratio, no heavy bowtie, even shoulders, symmetrical point, is much smaller than for rounds. When you buy a good oval you are buying out of a narrow band at the top of the production, and that band is priced accordingly. Plenty of cheap ovals exist. They are cheap because they are badly cut.

The two effects partly cancel. You pay more per carat, but you need fewer carats for the same face-up size. Compare millimetres, not carat weight, and the elongated shapes often still come out ahead.

Step cuts, emerald and asscher, sit differently again. They also spread, and they tend to be less expensive per carat than rounds, but they impose their own requirement, covered next.

Where to spend and where to save

This changes completely depending on the shape, and this is the part most price guides get wrong by giving one universal answer.

Brilliant cuts (round, oval, pear, cushion, radiant, marquise) have dozens of small facets scattering light in every direction. That facet pattern hides things. It hides inclusions and it hides body colour.

For a brilliant cut:

• Spend on cut. Excellent, or for fancies, verified good proportions and no heavy bowtie.
• Save on clarity. VS2 or a well chosen SI1 will be eye clean and nobody will ever know.
• Save on colour. G or H in white metal. H or even I in yellow or rose gold.
• Spend the difference on carat or on the setting.

Step cuts (emerald, asscher, baguette) have long parallel facets and a large open table. They act like a window into the stone. They hide nothing.

For a step cut:

• Spend on clarity. VS1 or better. An inclusion that would vanish in a round brilliant sits there in plain view in an emerald cut, and once you have seen it you cannot unsee it.
• Spend on colour. F or better, because an open table shows body colour clearly, especially in white metal.
• Spend on symmetry, because the parallel facet lines make any misalignment obvious.
• Save on carat if you have to, because step cuts spread and look larger than their weight.

That is the whole trade off in two lists. A one carat emerald cut and a one carat oval are not shopped the same way, and treating them the same is how people end up disappointed with a stone that graded well on paper.

Setting and metal

The mount is not an afterthought and it is a real part of the price.

Solitaire is the least expensive to make and the least expensive to maintain. Four or six claws, a clean band. It also shows the stone best.

Pavé and hidden halo settings add labour and add small stones, both of which add cost. They also add long term maintenance, because small stones set in a band get knocked and the setting wears.

Halo settings add cost but make a smaller centre look larger, which can be net cheaper than buying up in carat.

Metal: 14ct and 18ct white, yellow and rose gold, or platinum. Platinum costs more, both in metal price and in labour because it is harder to work. It wears differently: platinum displaces rather than loses metal, so claws thin more slowly. White gold is plated with rhodium and that plating wears off over a few years, revealing the slightly warm alloy underneath, so it needs replating periodically. Neither is better. They are different maintenance profiles and you should know which one you are choosing.

Band width and weight matter too. A 1.6mm band and a 2.4mm band in the same metal are different amounts of gold and different amounts of money, and the thinner one goes out of round faster.

Why prices have fallen

Lab grown diamond prices have dropped substantially since 2020. This is not a promotion and it is not going to reverse.

The reason is straightforward. Growing capacity expanded enormously as reactors were built out, particularly for CVD, and the technology improved at the same time. Yields went up, cycle times came down, and the number of producers multiplied. Any manufactured product with expanding capacity and improving process gets cheaper, and diamonds turn out not to be an exception.

Two honest consequences.

The good one: a specification that was out of reach a few years ago is now routine. Larger stones, better cut grades, better colour, for money that used to buy something modest.

The bad one: your ring will not hold its value, because the equivalent stone will be cheaper next year. We say this on every page where it is relevant, because it is the one thing that shocks people later. Buy a lab grown diamond because you want to wear it every day for forty years. Do not buy one as an asset. The longer comparison against mined stones is here.

What our pricing includes

Every ring we make comes with the same things, and they are worth counting into any comparison you do.

• An IGI certified centre stone, laser inscribed on the girdle with its report number
• A lifetime warranty on craftsmanship and on the optical properties of the stone
• One free resize within three months of purchase, up to four sizes either way, or two sizes on a pavé ring
• A free ring sizer posted to you before anything is cast, which you can request here
• Carbon offset delivery Australia wide, insured, signature required

Fingers change size, so a resize is a cost you should expect at some point. Ask what one costs before you compare two numbers. Ours start at $80 once the first free resize is used or the three months are up.

You can see the current range at lab grown diamond engagement rings, or book an appointment at the Southbank studio to look at stones in person. Design consultations by video call if Melbourne is not practical.

FAQ

How much is a 1 carat lab grown diamond ring in Australia?

It depends far more on cut, colour, clarity and the setting than on the carat weight, which is why a single number is misleading. Two one carat rings can differ by several thousand dollars on specification alone. Our lab grown diamond designs start at AU$1,350 and go up from there with the stone and the mount.

Why are lab grown diamonds so much cheaper than mined?

Production capacity expanded quickly and the technology improved, so the cost of growing a stone fell. There is also no rarity premium, because supply is not constrained by geology. The stone itself is chemically identical.

Will lab grown diamond prices keep falling?

Probably, though more slowly than in the first few years, as the easy gains in yield have already been made. Either way, plan on the ring being worth less than you paid if you ever sell it.

Is it cheaper to buy the stone and setting separately?

Not usually, and it introduces a real risk. A stone bought online and posted to a jeweller for setting is uninsured against a setting accident that nobody will claim responsibility for. When we supply both, the warranty covers both.

Does a bigger diamond always cost more per carat?

Yes, and the increase is not linear. Price per carat steps up at 1.00, 1.50, 2.00 and 3.00 carats. Buying just under a threshold, 0.90 instead of 1.00, or 1.90 instead of 2.00, saves real money for a difference in diameter you cannot see.