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Gemstone encyclopedia

Every gemstone, explained

What each stone is, how it wears in jewellery, and what to ask before you choose one. Browse by colour, or go straight to a letter.

This encyclopedia is educational. Inclusion does not confirm current Ralph Jacobs stock, sourcing, availability or suitability for a particular jewellery design.

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Quick overview

Laboratory-grown diamond

Laboratory-grown

A laboratory-grown diamond is diamond made by people in a laboratory or factory, using the HPHT or CVD growth method, rather than formed by nature.

Classification
Laboratory-grown material
Mohs hardness
10 (scratch resistance — one part of durability)
Wear considerations
For how diamond holds up in everyday wear, see the diamond entry. The durability section on this page explains, with sources, why that information applies to laboratory-grown diamond.
Treatment
HPHT annealing after growth, to change colour (post-growth treatments should be disclosed), Radiation and heating after growth, to change colour (post-growth treatments should be disclosed)
Care
If you are unsure how to clean or look after your piece, ask the jeweller who made it for their care and safety guide, and follow it. Keep any grading report with…
Explore the full gemstone guide Read the buying guide

Individual gemstones vary. Care depends on treatment, setting and condition. Encyclopedia inclusion does not confirm availability.

Individual gemstones vary · care depends on treatment, setting and condition · birthstone traditions vary · encyclopedia inclusion does not confirm availability.