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Nephrite:
Inosilicates (Hydrous calcium magnesium iron silicate; amphibole group) Ca2(Mg,Fe)5SiO22(OH)2 AKA: Actinolite |
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System: Monoclinic; usually long prismatic with diamond-shaped cross section; also bladed, acicular, columnar, divergent. Appearance: Bright to dark green, grayish green, black; vitreous, pearly, silky; streak colorless. Physical properties: Hardness:(5 - 6); Specific gravity: (3.0 - 3.5); Cleavage: perfect cleave parallel to the vertical prism; fracture, splintery, uneven; transparent to translucent. Similar species: Wollastonite is usually fluorescent; tourmaline has no cleavage; and epidote lacks the cleavage angle of actinolite. Occurrence: Nephrite is more common than jadeite. It is found in China, New Zealand, Tasmania, Burma, Brazil, Canada, Mexico, New Guinea, Taiwand and Poland. Miscellaneous: Nephrite is used as an ornamental stone in jewelry and is often confused with jadeite, which is more valuable. The name is from the Greek aktinos, "ray", in reference to the common radiate habit of prismatic crystals. Conventional Wisdom: Nephrite, meaning "kidney stone" owes its name to the European belief that it could cure kidney diseases. In New Zealand, the Maori carve nephrite into images of ancestral figures, usually with mother-of-pearl eyes. Called hei tiki, these figures are worn on ceremonial occasions. The stone itself is considered to be fortunate. Belongs to the Astrological Sign of Libra. |