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.
2 of 27 gemstone entries
Quick overview
Pearl
Pearls grow inside living molluscs, which makes them organic gems. Learn how lustre, shape, surface, size and nacre separate pearls, and how to care for such a soft gem.
- Classification
- Organic gem material
- Mohs hardness
- 2.5 (scratch resistance — one part of durability)
- Wear considerations
- Pearl ranks 2.5 on the Mohs scale, so it scratches easily. Acids, many chemicals, cosmetics, perfume, sweat and high heat can damage it. Strung pearls may need restringing from time to time.
- Treatment
- Dyeing, Bleaching, Impregnation, Coating
- Care
- Pearl is soft and easily scratched. Wipe it with a soft, clean cloth after each wear, and keep it away from sharp or rough objects. Keep pearls away from perfume, hair spray,…
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.