Know your Stones

Chalcedony

A mystical, magical appearance glowing through a silky lustre.

It has been suggested that Chalcedony was one of the earliest materials used by man. Not only has the stone been mentioned as one of the 12 gems in the breastplate of Aaron, there is reference to its use in creating the foundation of the city walls of the ‘New Jerusalem’.
In the 7th century BC, it was used to make cylindrical seals in the area of Mesopotamia. Over time, as well as being set in jewellery and carvings, Chalcedony has been shaped into knives and tools. In particular it is used to carve attractive cameos, and is one of the gemstones used in commesso; a technique of fashioning pictures with thin, cut-to-shape pieces of brightly coloured gemstones (extremely popular in the 16th century in Florence, Italy an important city during the Renaissance).

The names Agate and Chalcedony are in some countries interwoven and are used to describe all members of the Quartz family that have a micro or cryptocrystalline structure, as opposed to a single crystal structure as seen in the likes of Amethyst, Smokey Quartz and Citrine (these are described as crystalline gemstones).

Chalcedony is best thought of as a species name, rather than a gem name. Whilst most colours of Chalcedony have their own distinctive names: Carnelian, Chrysoprase, Lace Agate etc, some simply use a colour prefix in front of the species name. For example; Blue Chalcedony is a greyish blue coloured gem, Pink Chalcedony is more of a milky Rose Quartz colour than that seen in a vibrant pink Sapphire and Green Chalcedony is a light pastel colour.

The gem has a distinctive waxy lustre, and is normally translucent through to opaque.

This bewitching stone is thought to drive out dread, hysterics, melancholy, mental illness, and to reduce fever and prevent depression. Wearing Chalcedony promotes tranquillity and harmony, and is also said to stimulate creativity.

The gem is mined in various parts of the world including Brazil, Madagascar and Sri Lanka and is normally located in volcanic and sedimentary rocks.