metamorphic
Nephrite Jade
Tremolite-Actinolite solid solution series, Ca2(Mg,Fe)5Si8O22(OH)2
Hardness: 6.0-6.5 (Mohs), Color: Dark green to spinach green, Luster: Vitreous to greasy, Structure: Interlocking fibrous (monoclinic), Cleavage: None (splintery fracture), Specific Gravity: 2.90-3.03
- Hardness
- 6
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Physical properties
Hardness: 6.0-6.5 (Mohs), Color: Dark green to spinach green, Luster: Vitreous to greasy, Structure: Interlocking fibrous (monoclinic), Cleavage: None (splintery fracture), Specific Gravity: 2.90-3.03
Formation & geological history
Formed through regional or contact metamorphism of magnesium-rich limestones (dolomite) or ultramafic rocks in the presence of water; typically associated with serpentinite belts.
Uses & applications
Used extensively in jewelry, ornamental carvings, sculpture, and historically for durable tool making (axe heads).
Geological facts
Nephrite is tougher than steel due to its interlocking fibrous structure, making it extremely difficult to break. It has been used for thousands of years in Chinese culture as the 'Stone of Heaven'.
Field identification & locations
Identify by its greasy luster when polished and its extreme toughness. Found commonly in British Columbia (Canada), New Zealand (known as Pounamu), and Siberia. It feels heavier than common river stones of similar size.
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