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.
January
February
April
May
July
August
September
October
Quick overview · April birthstone
Diamond
Why diamond suits a ring worn for life, and where its limits are: how the 4Cs, cut, treatments, grading reports, setting and care shape how a diamond looks and wears.
- Classification
- Mineral species
- Mohs hardness
- 10 (scratch resistance — one part of durability)
- Wear considerations
- Diamond rates 10 on the Mohs scale, the highest rating, so only another diamond can scratch it. A hard blow along a cleavage direction can still split it, and pointed corners can chip. A loose diamond can wear through the metal prong that holds it.
- Treatment
- Heating or irradiation after growth to change colour (most CVD laboratory-grown diamonds receive such treatments)
- Care
- Diamonds can be cleaned at home with a lint-free cloth, a commercial jewellery cleaner or a household detergent. Abrasive cleansers are not recommended for home cleaning, and ultrasonic and steam cleaners can…
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.