A hard, dark green stone that is one of two minerals commonly called jade; the other is jadeite. Nephrite, a mixture ofactinolite and tremolite, is a calcium magnesium silicate with traces of chromium and nickel that produce its color. Nephrite is more opaque and usually darker than jadeite. Sources for nephrite include New Zealand, Australia, Taiwan (nephrite cat's eyes), Turkestan, Korea, Siberia, Mexico, Canada (British Columbia), and the U.S. (Alaska, California, Wyoming). Nephrite has an oily, lustrous appearance when polished. It is sometimes variegated in color and can incorporate white, yellow, brown, gray, and black shades. Nephrite has been used since Neolithic times for small utensils, decorative carvings and jewelry. The greenstone used by the Maoris of New Zealand is nephrite. When heated to about 1025 C, nephrite changes mineral forms to diopside.
Synonyms and Related Terms
jade; nephurite; greenstone, actinolite; tremolite; nefrita (Esp.); néphrite (Fr.); Nephrit (Deut.); nefriet (Ned.)
Monoclinic system with fibrous or granular crystalline masses.
Luster = vitreous to silky. Streak = colorless
Cleavage is good in two directions
Fluorescence: nephrite does not fluoresce
Max abs = doublet at 689 nm with sharp band at 509 nm and others at 460, 498 nm
° E.West Fitzhugh, "Jade" The Dictionary of Art, Grove's Dictionaries Inc., New York, 1996.° Michael O'Donoghue and Louise Joyner, Identification of Gemstones, Butterworth-Heinemann, Oxford, 2003 ° Mineralogy Database: actinolite
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- Michael O'Donoghue and Louise Joyner, Identification of Gemstones, Butterworth-Heinemann, Oxford, 2003 Comment: Hardness=6.5; RI=1.600-1.641; Specific gravity=2.96-3.02;
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- Website address 1 Comment: http://www.geo.utexas.edu/courses/347k/redesign/gem_notes/Jade/jade_triple_page.htm (fluorescence information)