Nephrite
a mineral, an aluminous variety of amphibole among the bisilicates, of a leek-green color, massive, and in rolled pieces, remarkable for its hardness and tenacity. It was formerly worn as a remedy for diseases of the kidneys. A unisilicate, zoisite, is also spoken of as nephrite, as is jade.
All three are capable of fine polish, and have been used since prehistoric times for ornaments, weapon-handles, and even weapons.