Mohs Hardness of 7 with a trigonal crystal structure
Chrysoprase is a cryptocrystalline, which means that the stone is composed of tiny crystals so fine that they are not able to be seen as distinct particles under normal magnification. This characteristic sets Chrysoprase apart from Rock Crystal, Amethyst, Citrine, as well as the other varieties of crystalline quartz. Those stones are basically transparent and formed from easily recognizable six-sided crystals.
Other members of the cryptocrystalline quartz family include Agate, Carnelian, and Onyx. Unlike many of the non-transparent members of the quartz family, it is truly the color of Chrysoprase, rather than a pattern of markings that makes it desirable.
Chrysoprase can be found in Australia, Brazil, the Ural Mountains, and in the USA. It is the valued form of the chalcedony group.