metamorphic
Nephrite Jade
Tremolite-Actinolite solid solution, Ca2(Mg,Fe)5Si8O22(OH)2
Hardness: 6.0-6.5 (Mohs), Color: Sage green to deep forest green, Luster: Vitreous to greasy, Crystal structure: Monoclinic (fibrous/interlocking), Cleavage: None (due to interlocking structure), SG: 2.9-3.0
- Hardness
- 6
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Physical properties
Hardness: 6.0-6.5 (Mohs), Color: Sage green to deep forest green, Luster: Vitreous to greasy, Crystal structure: Monoclinic (fibrous/interlocking), Cleavage: None (due to interlocking structure), SG: 2.9-3.0
Formation & geological history
Formed through the metamorphism of magnesium-rich limestones (dolomites) or through the hydrothermal alteration of ultramafic igneous rocks. It is found in mountain-building regions where tectonic plates collide.
Uses & applications
Extensively used for ornamental carvings, jewelry (beads, cabochons, bangles), and historical tool-making due to its extreme toughness.
Geological facts
Nephrite is one of two distinct minerals known as jade (the other being Jadeite). It is famous for its extreme toughness—it is harder to break than steel because of its interlocking felt-like fibrous structure.
Field identification & locations
Identify by its translucent green color, greasy luster, and extreme toughness. Commonly found as river boulders in British Columbia, New Zealand, Russia, and Wyoming, USA. It feels heavier than common green glass or plastic.
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