metamorphic
Polished nephrite jade
Nephrite jade; compact amphibole aggregate, chiefly tremolite–actinolite, Ca₂(Mg,Fe)₅Si₈O₂₂(OH)₂
AI-generated identification · may be incorrectHardness about 6–6.5 Mohs; dark green with brown/black inclusions, greasy to vitreous luster, translucent edges, and no visible cleavage. Its interlocking fibrous crystal structure gives exceptional toughness. The rounded, glossy surface indicates a tumbled or polished specimen.
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Physical properties
Hardness about 6–6.5 Mohs; dark green with brown/black inclusions, greasy to vitreous luster, translucent edges, and no visible cleavage. Its interlocking fibrous crystal structure gives exceptional toughness. The rounded, glossy surface indicates a tumbled or polished specimen.
Formation & geological history
Forms when magnesium-rich rocks undergo metamorphism and fluid alteration, commonly near serpentinite bodies; deposits are mainly Paleozoic to younger, though age varies by locality. The photograph cannot establish an exact locality or age.
Uses & applications
Used for carvings, beads, cabochons, ornaments, and historically tools and weapons; quality depends on vivid color, translucency, uniformity, and lack of fractures.
Geological facts
Nephrite is tougher than jadeite because of its felted amphibole fibers. Dark matrix and brown zones may represent iron-rich actinolite or included host material.
Field identification & locations
Field identification: unusually tough green stone, waxy/greasy polish, fibrous texture under magnification, and typically no cleavage; verify with hardness, density, and laboratory testing because serpentine, dyed quartz, and glass can look similar. Common sources include China, British Columbia, Siberia, New Zealand, and Wyoming.
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