Chrysoprase is a green coloured form of Chalcedony, a crypto-crystalline variety of quartz. It is one of the rarest and most highly prized varieties of chalcedony.  The best quality material is mined from the famous Marlborough deposits near Rockhampton in Central Queensland which is where this material originates.

With a MOH’s hardness of 6 - 7, this gemstone has a medium green colour and translucency  similar to the best Jadeite.