Characteristics and Identification of Glass Imitation of Green Nephrite

A kind of glass imitation of green nephrite appearing in the present Chinese market is studied by using the conventional gemmological methods, microscopic section observation, EMPA and infrared spectroscope．The results show that the glass imitation is a kind of opacified devitrified glass, mainly composed of SiO₂ and Al₂O₃, subordinate alkali metal oxide of K, Na, Ca, Mg and other precipitate of calcium fluoride and calcium phosphate．The glass imitation could be identified through such methods as dull colour, sometimes with white spot, lower specific gravity and hardness, conchoidal fracture, fern-vein-like structures and diagnostic infrared spectrum．