Lab-grown vs natural diamonds: how to decide

Origin is the main built-in difference. A natural diamond formed deep in the earth, at a depth of about 160 km (100 miles) below the surface, and was carried up long ago. A lab-grown diamond is grown by people, in a press or a vacuum chamber, from a thin slice of diamond called a seed.

Chemically they are the same thing. GIA describes diamond as typically about 99.95 per cent carbon, with an isometric crystal structure, and says lab-grown diamonds share that crystal structure and have nearly the same chemical, optical and physical properties as natural ones. Simulants such as cubic zirconia and moissanite, by contrast, are unrelated to diamond at the atomic level. That is why hardness, sparkle and the care routine are essentially the same for both kinds of diamond. Only a diamond can scratch a diamond, and any stone, diamond included, can chip if it is hit hard enough in the wrong place.

What differs is everything that follows from origin: how the stone is described and sold, how a lab reports on it, how the price behaves, and how it fits your own view of what a diamond should be. The table below sets the two side by side, with moissanite included because many buyers compare all three.

There are two methods, and both start from a diamond seed. In high-pressure, high-temperature growth (HPHT), the seed sits in a press heated to roughly 1,300 to 1,600 °C at pressures of about 6 GPa (more than 870,000 psi). A molten metal flux of iron, nickel or cobalt dissolves a carbon source, and the carbon crystallizes onto the seed over days to weeks. HPHT crystals tend to grow with cube faces as well as the octahedral faces natural crystals show.

In chemical vapour deposition (CVD), a hydrogen and carbon-containing gas, such as methane, fills a vacuum chamber and is broken down by an energy source such as a microwave beam. The carbon atoms drift down onto seed plates over several weeks, at lower temperatures (around 900 to 1,200 °C) and lower pressure than HPHT.

Some stones are treated after growth. GIA notes that most colourless CVD material on the market was probably brown when it grew and was then lightened by HPHT annealing. Treatment is common with these stones, which is why a good report states it. Natural diamonds can be treated too, so the same question applies to both.

No. GIA says a colourless CVD diamond can look the same as a natural diamond to the unaided eye and that a gemmological laboratory is needed to identify it. Labs use instruments such as DiamondView, which images the growth patterns inside the crystal, along with spectroscopy. The growth conditions leave markers: HPHT stones can show uneven colour and geometric patterns, and CVD stones can show banded strain under polarized light.

That has a practical consequence. You cannot check origin yourself in a showroom, so you rely on paperwork and marking. A report from a recognized lab, such as GIA or IGI, states whether the stone is natural or laboratory-grown. GIA also laser-inscribes the girdle of the lab-grown diamonds it reports on with the words ‘Laboratory-Grown’ and its assessment number, so the stone itself carries its origin.

The same logic applies to a ring with many small stones. If a pavé band or halo is set with a lot of small diamonds, ask in writing whether every stone has the same origin as the centre stone.

The main federal rule that governs how a seller describes a stone is general rather than diamond-specific. Under paragraph 74.01(1)(a) of the Competition Act, it is a reviewable practice to make a representation to the public that is false or misleading in a material respect. The Competition Bureau says a court weighs both the literal meaning of the words and the general impression they create, and that information is material if it could influence a buyer to purchase.

For lab-grown diamonds, that general rule meets industry guidance. The Canadian Jewellers Association’s lab-grown advertising guidelines, released on February 28, 2020, say ‘synthetic’, ‘lab-grown’ or ‘lab-created’ must sit immediately before the word ‘diamond’, with neither word given more prominence and nothing between them. These are an industry association’s guidelines, not a statute, but they show the standard the trade sets for itself.

Two outside points help. The US Federal Trade Commission’s Jewelry Guides (US rules, not Canadian) define a diamond by its composition, ‘a mineral consisting essentially of pure carbon crystallized in the isometric system’, rather than by origin, and allow ‘cultured’ only with a clear disclosure such as ‘laboratory-grown’. And in September 2025 the international body CIBJO recommended ‘synthetic’ as the sole descriptor when communicating to an international audience, while acknowledging that national law takes precedence. ‘Lab-grown’, ‘laboratory-grown’ and ‘synthetic’ are all used for the same stone, so read the invoice for whichever word it uses.

Not always, and this is a recent change. GIA’s reports on lab-grown diamonds used to use the same four Cs language as for natural ones: carat weight, colour, clarity and cut. GIA announced on June 2, 2025 that it would stop using the colour and clarity terms created for natural diamonds on lab-grown diamonds. Its reason: more than 95 per cent of lab-grown diamonds entering the market fall into a very narrow range of colour and clarity.

Since October 1, 2025, GIA’s Laboratory-Grown Diamond Quality Assessment, for colourless to near-colourless stones of 0.15 ct and up, classifies each stone as Premium or Standard, and a stone that does not meet the Standard criteria gets no assessment. Other labs make their own choices about report format, so check which scale a report uses before comparing two stones. The guide to reading a grading report and the four Cs guide cover the details.

The practical point is that a natural stone graded G, VS1 and a lab-grown stone described as Standard are not described in the same language. Compare stones by what the report shows (shape, measurements, cut, polish, symmetry, and the colour and clarity information it gives), not by the label alone.

A lab-grown diamond is made rather than found, and De Beers describes lab-grown pricing as moving toward a cost-plus model, meaning cost of production plus a margin. A natural diamond has to be found and mined first, so its price carries those costs and the effect of supply.

The record of the past few years is one-directional. Bain & Company’s 2021–22 report found that in 2021 the average polished lab-grown price had fallen to 30 per cent of the natural price at retail and 14 per cent at wholesale, down from 35 and 20 per cent in 2020. On May 8, 2025, De Beers, which mines natural diamonds and has a stake in how the two are compared, said lab-grown prices in the jewellery sector had fallen 90 per cent at wholesale. Weigh that source with its position in mind, but note that the direction matches Bain’s earlier finding.

No one can forecast where lab-grown prices go next. What those sources support is narrower: lab-grown stones have been priced below natural stones of the same size and grade, and between 2020 and 2025 the gap widened rather than narrowed. For current numbers, ask for quotes on both at the same carat weight, shape and grade. The engagement ring budget guide shows how to weigh a stone’s price against the rest of the ring.

Plan on the assumption that you will keep the ring. Jewellery is often bought at retail and sold for less, and neither type of diamond should be bought with the expectation of selling it back at the price you paid.

There is a specific reason to be cautious with lab-grown stones. Lab-grown prices fell sharply in the sources above, so a lab-grown stone bought earlier may be competing with new stones at lower prices if you sell. What you receive for either kind depends on the buyer, the grade and the market.

If resale or trade-in matters to you, get the terms in writing before you buy: whether the seller will buy the stone back or credit it toward another purchase, for how long, at what percentage of the price, and whether the answer is different for natural and lab-grown stones. A jewellery appraisal is a separate matter. It estimates a replacement value for insurance and is not a measure of what a buyer would pay.

You will meet both types of claim on both types of diamond, so it helps to know what each can and cannot mean.

For natural stones, the usual label is ‘conflict-free’, which refers to the Kimberley Process. That scheme describes itself as an international initiative to exclude conflict diamonds from the legitimate trade, and it covers rough diamonds. It is a narrow, defined commitment, so when you see a sourcing claim, ask what exactly it rests on and ask for it in writing. For the fuller picture of stones mined in Canada, see the article on Canadian diamonds.

For lab-grown stones, the usual claim is that they are better for the environment. Canadian law regulates this kind of claim. The Competition Act requires that claims about a product’s environmental benefits be based on adequate and proper testing, and claims about a business’s environmental benefits on adequate and proper substantiation. The Competition Bureau’s guidance asks that such claims be truthful, specific, not exaggerated and not vague. An amendment in the Budget 2025 Implementation Act, No. 1, which received Royal Assent on March 26, 2026, removed the requirement that business-level claims follow an internationally recognized methodology; the testing and substantiation requirements remain.

This guide makes no claim that either type is cleaner or more ethical. A seller who says so should be able to show you the evidence behind the statement, and that is a fair thing to ask for.

There is no universally right answer. Both are diamonds, and the choice comes down to what you value. These are the trade-offs as they stand.

• Choose lab-grown if the main goal is the most size, quality and design for your budget, and you are comfortable that the stone’s origin is a factory rather than the earth. For many buyers the saving goes into a larger stone, a better cut or a more detailed setting.
• Choose natural if the geological origin matters to you, if you value a stone that formed over a very long time and cannot be made on demand, or if the tradition of a mined diamond is part of the meaning you want. Expect to pay more for the same size and grade.
• Consider moissanite if you want a diamond-like look at a lower price and do not need the stone to be a diamond. It is a different material.
• Mix them if you like. A design can pair a natural centre stone with lab-grown side stones, or the reverse, as long as the origin of each stone is stated.

Whichever you choose, size and shape come before the label. The guide to choosing an engagement ring and the diamond shapes guide cover the decisions that change how the ring looks and wears more than origin does.

These questions work for any seller, in a showroom or online.

1. Is the stone natural or laboratory-grown, and does the invoice say so in plain words next to the word ‘diamond’?
2. Is there a report from a recognized lab, and does its number match the one inscribed on the girdle?
3. Has the stone been treated? Some lab-grown stones are treated after growth, and natural stones can be too.
4. Does the report give the colour, clarity, cut, polish and symmetry for this stone, and which scale does it use?
5. If the ring has many small stones, are they all the same origin as the centre stone?
6. What does the seller say about resale, trade-in or upgrade, and is it in writing?
7. If the seller makes an environmental or sourcing claim, what is the evidence behind it?
8. What are the return and resizing terms, and do they differ between natural and lab-grown stones?

A seller who answers these directly and puts the answers on paper is giving you what you need to compare. Hesitation on question 1 or 2 is a reason to keep looking.

Moissanite is not a diamond, lab-grown or otherwise. GIA describes simulants such as moissanite as unrelated to diamond at the atomic level. It is a separate material that is grown in laboratories for jewellery and sold under its own name. It is a lower-priced alternative to both kinds of diamond and is worth seeing in person if budget is the deciding factor. Fancy-coloured stones are a separate topic again: a fancy-coloured diamond can also be natural or lab-grown, and the same disclosure and report questions apply.

A custom ring lets you decide the stone’s origin separately from the design. At Diamond Bros, a custom engagement ring can be made with a natural diamond, a lab-grown diamond or moissanite, and the same applies to custom jewellery design for other pieces. The design studio lets you start from a shape and setting, and the engagement rings collection shows finished examples. If you would rather compare stones side by side, the showrooms are the place to ask the questions in the list above. The custom engagement ring process guide explains what happens from first sketch to finished ring.