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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 · April · As listed by GIA

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…
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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.