Nephrite Jade
Nephrite (Ca2(Mg, Fe)5Si8O22(OH)2)
Rock Type: metamorphic

Physical Properties
Hardness: 6.0-6.5 Mohs scale; Color: Dark green to black; Luster: Vitreous to greasy; Crystal Structure: Monoclinic (fibrous aggregate); Cleavage: Indistinct; Specific Gravity: 2.9-3.0.
Formation & Geological History
Formed through contact metamorphism of magnesium-rich limestones or through the alteration of ultrabasic rocks by hydrothermal fluids. Often found in serpentinite deposits.
Uses & Applications
Extensively used for ornamental carvings, jewelry (cabochons and beads), and historically for tools and weapons due to its extreme toughness.
Geological Facts
Nephrite is significantly tougher than diamond despite its lower hardness score because of its interlocking fibrous structure, making it very difficult to break or chip.
Field Identification & Locations
Identify by its soapy or greasy feel and extreme toughness. Commonly found in riverbeds as water-worn cobbles in British Columbia, New Zealand, Russia, and China.
Identified on: 5/20/2026
Mode: Standard