DESCRIPTION
As a form of chalcedony (type of quartz) agate exhibits a variety of colours, shapes, as well as an often present gentle iridescence.
Agate is a mineral that has been mined for many, many years. It has been mined in some of the beautiful locations around the world including the world famous Idar-Oberstein, but today the main supply of the very versatile gemstone is Brazil.
Agates occur as nodules in volcanic rocks or ancient lavas, then filled, wholly or partially, by siliceous matter deposited in regular layers upon the walls.