Natural and lab-grown diamonds are chemically, physically and optically identical; the difference is origin. Natural stones formed underground over billions of years, while lab-grown stones are produced in weeks in a laboratory. For trade buyers the practical differences are price, resale expectations and the disclosure rules that apply when you sell.
How lab-grown diamonds are made
Lab-grown diamonds are produced in two ways. The high-pressure, high-temperature method reproduces the conditions deep in the earth using intense heat and pressure, while chemical vapour deposition builds a diamond layer by layer from a carbon-rich gas. Both produce a genuine diamond with the same crystal structure as a mined stone, not a simulant such as cubic zirconia or moissanite. Growth takes weeks rather than geological time, and the stones are then cut and polished like any other diamond.
How the two are graded
Once cut, both are graded on the same four Cs, and both can be certified by an independent laboratory. Natural diamonds are commonly supplied with a GIA grading report, which records carat weight, colour, clarity, cut, polish, symmetry and fluorescence. Lab-grown stones are graded on the same scale, with the report identifying the stone as laboratory-grown. Whatever the origin, the certificate is what lets you describe the stone accurately and price it fairly, and it should travel with the stone.
How to tell them apart
You cannot separate a lab-grown diamond from a natural one with a jeweller's loupe, because the two are the same material. Identification relies on laboratory equipment, on the grading report, and on laser inscriptions on the girdle, which typically carry a report number and, for lab-grown stones, a statement of origin. Where a stone is supplied loose without paperwork, treat the origin as unverified until it has been checked by a laboratory.
Price and resale: the real trade difference
The clearest trade difference is price. Lab-grown stones sell for less than natural stones of comparable size and quality, and their prices have fallen further as production has scaled. The second difference is resale: the market for second-hand natural diamonds is long established, while the second-hand market for lab-grown stones is thinner and less predictable. For a jeweller, that affects both the margin on the initial sale and what a customer can realistically expect if they later want to trade a stone in.
What you must disclose when you sell
A lab-grown diamond must never be described as natural, and UK consumer protection law requires goods to be accurately described. Beyond the legal position, clear disclosure protects your reputation: a customer who later discovers that a stone was laboratory-grown, and was not told, will not trust the next purchase. Trade guidance in the UK and internationally requires terms such as laboratory-grown, laboratory-created or synthetic, and prohibits using the unqualified word diamond to imply natural origin.
Should you stock both?
That depends on your customers and your price points. Many jewellers stock both and let the customer choose between a larger lab-grown stone and a smaller natural one at the same budget, which is a clear and honest conversation to have. Others specialise in one category. What matters is that your stock records, your labelling and your staff all distinguish the two without ambiguity, so the disclosure is automatic rather than remembered.
Sourcing both from one supplier
Sourcing both from a single diamond house keeps your records consistent and your disclosure straightforward. Caesar Diamonds supplies wholesale diamonds to the trade, natural stones with GIA grading reports and lab-grown stones with grading documentation, with every certificate and provenance detail logged against the order in Caesar Track. Our natural diamonds comply with the Kimberley Process Certification Scheme, which applies to rough natural diamonds. Read the natural vs lab-grown guide in context for how ordering works.