Lab-grown and mined diamonds

What a lab-grown diamond is

A diamond is carbon in a particular crystal structure. A lab-grown diamond has that same structure, grown in equipment that reproduces the conditions under which diamonds form. It is not a simulant. Cubic zirconia and moissanite are different materials with different optical behaviour. A lab-grown diamond is a diamond.

The hardness is the same: 10 on the Mohs scale. The refractive index is the same, so light behaves the same way inside the stone. A trained grader cannot separate the two by eye or with a standard loupe. Laboratories identify origin using specialist instruments that read growth patterns and trace elements.

How they are grown

Two methods are used commercially. Both produce gem-quality rough that is then cut and polished in the same way as any other diamond.

• CVD, chemical vapour deposition. A carbon gas is broken down in a vacuum chamber and carbon settles layer by layer onto a thin diamond seed.
• HPHT, high pressure high temperature. Carbon is subjected to the pressure and heat at which diamond is the stable form.

Growth takes a few weeks. Every Venera stone lists its method on the product page, under growth method.

How they are graded

By the same laboratories, on the same scales. Our stones are certified by IGI or GIA and graded for colour, clarity, cut, polish and symmetry exactly as mined diamonds are. The report number is printed on each product page and links to the laboratory's own database, so you can check it yourself before you buy.

Lab-grown reports state that the stone is laboratory-grown, and the stone itself usually carries that inscription on the girdle, readable under magnification.

Price

Lab-grown diamonds cost less per carat than mined diamonds of comparable grade. Supply is the reason: production can be scaled, so the price is set by manufacturing rather than by extraction and distribution.

In practice this means a given budget reaches a larger stone, a higher colour and clarity grade, or both. It is the main reason our customers give for choosing lab-grown.

Resale

Worth knowing before you spend: lab-grown diamonds have a limited resale market, and prices per carat have fallen as production has grown. Buy one to wear, not as an investment. The same caution applies more widely than people expect — retail jewellery of any origin rarely resells for close to its purchase price.

Choosing between them

Both are diamonds. Mined stones carry a geological history and a market that has existed for a century. Lab-grown stones offer the same material at a lower price with a traceable origin. Neither choice is wrong, and we are not going to tell you your reasons.

Venera sells lab-grown only. Everything in our catalogue is certified, and every certificate is verifiable. The 4Cs explains what the grades on those certificates mean.

Terminology: some markets require lab-grown stones to be described as such in all advertising. We do that on every page, as a matter of course.