Also known as cornelian, this translucent, reddish orange variety of chalcedony was once thought to

Bloodstone (also known as heliotrope) are opaque, green, spotted varieties of chalcedony, used for decorative

Agate occurs in nodular masses in rocks such as volcanic lavas. When split open, they

Chalcedony is a cryptocrystalline form of silica, composed of very fine intergrowths of the minerals

Celestite or celestine is generally found as colourless, milky white, yellow, orange or pale blue

Calcite is a mineral named after its calcium content. It is one of the most

Very rare and seldom seen as a cut stone, red beryl nonetheless has an unusually

Heliodor, a yellow or golden yellow form of beryl, has always been linked with the

Emerald derives its beautiful green colour from the presence of chromium and vanadium. Emeralds are

In the 19th century the preferred color for aquamarine was sea-green, and indeed the name

Beryl is a beryllium aluminium silicate with the chemical formula Be3Al2(SiO3)6. The hexagonal crystals of

The blue crystals of benitoite were only discovered in 1906, by a mineral prospector who

Barite or Baryte occurs in a number of colours, including colourless, white, yellow and blue,

Azurite is an azure-blue copper mineral, occasionally found as prismatic crystals (rarely faceted), but more