Lab-grown diamonds, explained properly.

A lab-grown diamond is diamond. It is crystallised carbon with the same crystal structure, the same hardness (10 on the Mohs scale) and the same optical behaviour as a stone formed underground. A gemmologist cannot separate the two by eye. The difference is that growth happens in weeks in a controlled reactor rather than over geological time.

Two growth methods dominate. In CVD (chemical vapour deposition), a carbon rich gas is broken down and carbon settles layer by layer onto a thin diamond seed. In HPHT (high pressure, high temperature), a seed is held in molten metal under extreme pressure and heat so carbon crystallises around it. Both produce gem quality material, and both are identified as laboratory grown on the certificate.

The material is the same, so the real differences are commercial and ethical. A lab-grown stone of a given cut, colour and clarity costs a fraction of the mined equivalent, which is why our 3ct emerald cut sits at $3,799 NZD rather than a multiple of it. Origin is fully traceable, with no mining footprint and no unresolved provenance.

The honest caveat: lab-grown diamonds are not an investment. Prices for the category have fallen as production has scaled, and resale value on any jewellery, mined or grown, is poor. Buy a piece because you want to wear it, and buy the best cut you can rather than the largest number.

If you have a fixed budget, the order we would spend in is cut, then carat, then clarity, then colour. A D VVS2 stone with a mediocre cut will always look duller than a well cut stone one grade lower.

IGI (International Gemological Institute) is an independent laboratory that grades diamonds and issues a report. A lab-grown report states the growth method, shape and cutting style, measurements, carat weight, colour grade, clarity grade, cut, polish and symmetry, fluorescence and the report number.

Every RW centre stone is IGI graded and laser inscribed on the girdle with its report number, readable under magnification. Before a piece leaves us, we match the inscription against the report, so the stone you receive is the stone documented. When you compare two quotes, compare the full report, not just the carat weight: cut grade, polish and symmetry explain most price differences that look unexplained.

Shape is personal, and it changes how the same carat weight reads on the hand. If you are between two, see them side by side on the full collection.

We work in 9k, 14k and 18k yellow, white and rose gold, and in platinum. Higher karat gold means more pure gold and a richer colour; 9k is harder and more affordable. Platinum is denser, naturally white and needs no rhodium plating, so it holds its colour without maintenance.

White metals make a D colour stone read as cold and bright. Yellow gold warms the same stone visually. If you have a nickel sensitivity, ask for a nickel-free 14k or 18k white gold alloy. For sizing, use the ring size guide.

1. 1Set the shape first. It drives how large the stone reads and which settings work.
2. 2Choose cut quality before carat weight. Light return is what people notice.
3. 3Stay eye clean rather than chasing Flawless. VS1 to VVS1 is invisible without a loupe.
4. 4Ask for the IGI report number and check the girdle inscription on arrival.
5. 5Consider the setting's longevity: claw counts, bezels and band thickness all affect daily wear.