metamorphic
Nephrite Jade
Ca2(Mg,Fe)5Si8O22(OH)2 (Tremolite-Actinolite series)
Hardness: 6.0-6.5; Color: Dark forest green; Luster: Vitreous to greasy; Crystal Structure: Monoclinic (fibrous microstructure); Cleavage: Indistinct; Specific Gravity: 2.9-3.0; Extremely tough and resistant to fracturing.
- Hardness
- 6
- Color
- Dark forest green
- Luster
- Vitreous to greasy
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Physical properties
Hardness: 6.0-6.5; Color: Dark forest green; Luster: Vitreous to greasy; Crystal Structure: Monoclinic (fibrous microstructure); Cleavage: Indistinct; Specific Gravity: 2.9-3.0; Extremely tough and resistant to fracturing.
Formation & geological history
Formed through the regional metamorphism of magnesium-rich rocks (dolomites) or mafic/ultramafic igneous rocks. It is found in rocks ranging from Precambrian to Cenozoic ages.
Uses & applications
Extensively used for ornamental carvings, jewelry, cabochons, and sculpture. Historically used for axle-heads and weapons due to its extreme toughness.
Geological facts
Nephrite is significantly tougher than Jadeite, despite being slightly softer. Its interwoven fibrous structure makes it one of the most durable natural materials. In ancient China, it was known as the 'Stone of Heaven'.
Field identification & locations
Identify by its waxy luster, extreme toughness (it will not break easily when struck), and lack of visible grains. Often found in alluvial deposits (river beds) near serpentinite belts in locations like British Columbia, New Zealand, and Russia.
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