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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

Salt-and-pepper diamond

A natural diamond with many visible inclusions. Heavily included black diamonds still rank 10 on the Mohs scale [cite ref="s6"]. Many inclusions near the edge make chipping more likely [cite ref="s1"].

Classification
Trade description within the mineral species diamond
Mohs hardness
10 (scratch resistance — one part of durability)
Wear considerations
Heavily included black diamonds still rank 10 on the Mohs scale, but their many tiny fractures can make them more brittle and prone to chipping if struck sharply [cite ref="s6"]. Diamond is only somewhat tough, and many inclusions near the girdle or points make chipping more likely [cite ref="s1"]. Points are better protected by bezels, partial bezels or V-shaped prongs.
Treatment
Laser drilling to improve clarity, Fracture filling to improve clarity (not permanent), Heating to graphitise fractures and turn a greyish, heavily fractured diamond black
Care
Clean your salt-and-pepper diamond with mild soap and water. Skip ultrasonic and steam cleaners, which are not advised for heavily included black diamonds. Avoid hard knocks, such as against countertops, and avoid…
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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.