Free Gem Guide

The Gem Guide is open to everyone without an email signup. Learn about gemstone families, birthstones, cuts, treatments, hardness and the questions worth asking before you buy.

Choosing a gemstone

Start with the stone's identity, colour and intended use. Compare the photographs with its listed weight, dimensions, cut, treatment and origin. Ask for a laboratory report when a particular identity or origin claim matters to your decision; a report only supports what it actually states.

Cut, shape and light

Shape describes the outline, such as oval, round or pear. Cut also concerns proportions and facets, which affect how light returns to the eye. Check a stone in more than one lighting condition, and look for dark areas or a pale window through its centre.

Hardness and care

Mohs hardness describes resistance to scratching, not toughness against knocks. Suitability for a ring also depends on cleavage, inclusions, setting and how it will be worn. Store pieces separately and ask about care before using heat, chemicals or ultrasonic cleaning.

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