Chrysoprase

Chrysoprase, often mis-labelled "chrysophrase", is a gem variety of chalcedony. Until polished it has a talc-like finish, and is the rarest member of the chalcedony family, with a Moh's scale hardness of 7. High quality specimens can rival jade for color and beauty.
Chrysoprase is found in Australia, Brazil, the Ural Mountains, and the U.S.
You may see beads marked as "Chinese Chrysoprase". This is not actually chrysoprase, but actually serpetine or jasper with a similar color to natural chrysoprase. However, unlike Chinese Chrysoprase, the actual gemstone never has black inclusions.
Chrysoprase was used by many ancient cultures in jewelry and ornamentation, including the Greeks, Romans, and Egyptians.