Lab-grown diamond jewellery: what to tell your customer

What it is, in two sentences

A lab-grown diamond is diamond: crystallised carbon, grown in a factory over days to weeks instead of formed in the earth. The Gemological Institute of America (GIA) says its chemical and physical properties correspond very closely to those of mined diamond, and it separates lab-grown diamond from imitations such as cubic zirconia, which are easy to identify.

The difference is origin. Lab-grown stones can look the same to the unaided eye, and telling them apart takes specialist laboratory instruments. That is the reason the paperwork and the wording on your tag matter.

HPHT and CVD in plain terms

There are two growth methods. Your customer does not need the chemistry, but your staff should be able to say one sentence about each.

• HPHT (high pressure, high temperature) recreates the heat and pressure of the earth. Carbon dissolves in a molten metal flux, usually iron, nickel or cobalt, and crystallises onto a small diamond seed over days to weeks.
• CVD (chemical vapour deposition) grows diamond from a carbon-bearing gas, typically methane with hydrogen, in a vacuum chamber at lower temperatures and pressures than HPHT. Microwaves break the gas down and carbon builds up in thin layers on seed plates over weeks.

Post-growth treatment and why reports mention it

Rough CVD crystals can come out brownish, and HPHT annealing is commonly used to remove it, according to GIA. This is why IGI reports carry a comment on growth process and treatment. Where there is no indication of treatment the report says the stone is as grown. For other CVD stones the report says it may include post-growth treatment.

Neither wording makes a stone better or worse. It is a material fact, and the same disclosure principle applies as for treated gemstones generally.

Reports: loose stones and finished jewellery

Both IGI and GIA grade lab-grown diamond, and the reports differ. IGI's Laboratory Grown Diamond Report grades carat, colour, clarity and cut on the same scales used for mined diamond, names the growth process in a comment, and records an inscription number that matches the report. GIA does not use the D-to-Z colour letters for lab-grown diamond. Since 1 October 2025 its service for colourless to near-colourless lab-grown diamond is a quality assessment: each stone is labelled Premium or Standard from an overall view of clarity, colour and cut, the minimum size is 0.15 ct, and a stone that misses the Standard minimums receives no assessment. The girdle is inscribed 'Laboratory-Grown' with the assessment number.

A loose-stone report grades one stone that the laboratory could see all the way round. Finished jewellery is different. IGI issues a separate Lab Grown Diamond Jewelry Report, with a yellow cover, that describes the article and identifies every mounted gemstone and any metal purity stamps. For a centre stone it gives shape, measurements and the 4Cs as mounting permits. For a multi-stone piece such as a tennis bracelet or a diamond-set ring, a sample IGI jewellery report lists a count of stones, a total estimated weight, and colour and clarity as ranges, for example E–F and VVS–VS, noted as graded as mounting permits.

So a jewellery report is a statement about the piece, not a certificate for each stone. Say that to the customer rather than letting them assume otherwise.

• Match the inscription on a centre stone to the report number under magnification.
• Verify every report number on the laboratory's own site (IGI 'Verify your report', GIA 'Report Check').
• Ask your supplier which pieces come with a report, and whether it is a loose-stone or jewellery report.

Disclosure: the Australian position

The general law applies to lab-grown diamond as it does to any other goods. Under the Australian Consumer Law, section 18 prohibits misleading or deceptive conduct in trade or commerce, section 29 prohibits false or misleading representations about goods, and section 33 prohibits conduct liable to mislead the public about the nature, manufacturing process or characteristics of goods. For a company, the maximum penalty for a false or misleading representation is the greatest of $100 million (for conduct from 28 March 2026; it was $50 million before then), three times the benefit obtained, or, where the benefit cannot be determined, 30% of adjusted turnover during the breach period.

The Australian Competition and Consumer Commission (ACCC) published Advertising and Promotion in the Jewellery Industry in 2005. It sets out the ACCC's views on disclosing treatments and on how terms such as 'synthetic', 'created', 'cultured' and 'imitation' are used for laboratory-made stones, and it warns that inflated 'valued at' figures in comparative pricing can mislead. It predates mainstream lab-grown jewellery, so treat it as a starting point and check the ACCC site for current guidance.

Overseas benchmarks are clearer and worth writing to. The UK Advertising Standards Authority's guidance (October 2025) says 'diamond' should always carry a qualifier such as laboratory-grown, and it found 'real diamond' misleading. The US Federal Trade Commission's 2018 Jewelry Guides allow lab-grown stones to be called diamond only with a clear qualifier. CIBJO, the World Jewellery Confederation, prefers 'laboratory-grown diamond', treats 'laboratory-created' and 'synthetic' as synonyms, wants the qualifier as conspicuous as the word 'diamond' and placed immediately before it, and asks that the term is not abbreviated.

Words to use and words to avoid

Put the qualifier everywhere the customer meets the stone: tag, website title, invoice, valuation and insurance schedule, and social captions. A correct tag does not rescue a receipt that says only 'diamond ring'.

• Use: laboratory-grown diamond, laboratory-created diamond. Use 'natural diamond' or 'mined diamond' for the other.
• Avoid: natural, real, genuine, cultured or cultivated attached to a lab-grown stone. CIBJO's guidelines rule these out, and the ASA found 'real diamond' misleading.
• Avoid blanket claims such as ethical, green, sustainable or eco-friendly. CIBJO asks that any such claim be substantiated and verified by an independent third party. The Australian Consumer Law applies to environmental claims like any other representation.
• On a mixed invoice, state which stones are lab-grown and their total weight.

Talking about mined diamond fairly

You do not need to run down mined diamond to sell lab-grown. The Kimberley Process and the United Nations estimate conflict diamonds at less than 0.1% of world production, so implying that mined stones are mostly conflict stones is both wrong and avoidable. Some customers value a stone formed in the earth. Others value size for the budget. Both are legitimate reasons.

Do not promise resale value, rarity or investment return for either product. Say what is true: both are diamond, they differ in origin, and the price reflects that.

Price positioning without overselling

We do not quote price figures here because lab-grown pricing has moved and any number would date quickly. If you compare against mined diamond in your shop or ad, compare like for like on carat, colour, clarity and cut, use a dated source, and write the date on it.

Position on what the customer gets: a larger or better-specified stone for a budget, or the same stone for less. Do not use a mined-diamond price as the 'valued at' or 'was' figure for a lab-grown piece. The ACCC has said valuations used in comparative pricing should reflect the normal price in the market where the item is sold.

SVN Diamonds supplies lab-grown diamond and gold jewellery to Australian jewellers. If you want to see the range, the catalogue and trade application are on this site.