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.
27 of 27 gemstone entries
Explore birthstones. Some months have several recognised stones and birthstone traditions vary. Association does not determine suitability, value or availability.
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Quick overview · November birthstone
Citrine
Citrine is the warm yellow-to-orange variety of quartz. Most is heat-treated amethyst. It rates 7 on the Mohs scale and needs care to avoid scratches, heat and sudden temperature changes.
- Classification
- Mineral variety
- Mohs hardness
- 7 (scratch resistance — one part of durability)
- Wear considerations
- Citrine rates 7 on the Mohs scale and has good toughness, so it suits all jewellery types, including rings, as long as the wearer understands its limited hardness. Sand and dust are mostly quartz and can scratch it, and sudden temperature changes can cause it to fracture.
- Treatment
- Heat treatment of amethyst, which turns purple quartz yellow. CIBJO's Blue Books distinguish heated amethyst from natural citrine, while noting that both are sold as citrine., Heat treatment of smoky quartz, which can produce lime-coloured citrine
- Recognised sources
- Notable locality
- Care
- Clean citrine with warm, soapy water. Ultrasonic cleaners are usually safe, unless the stone is dyed or fracture-filled. Steam cleaning is not recommended, because citrine should not be exposed to heat. Protect…
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.