![Nephrite Jade (Pounamu) (Nephrite [Ca2(Mg, Fe)5Si8O22(OH)2]) — metamorphic](https://media.rockidentification.com/6686f634-7bf1-4bc7-a5cf-9f5abc2a26ee-compressed.jpg)
metamorphic
Nephrite Jade (Pounamu)
Nephrite [Ca2(Mg, Fe)5Si8O22(OH)2]
Hardness: 6.0-6.5 on Mohs scale; Color: Dark green to light grey-green; Luster: Greasy to waxy; Crystal structure: Monoclinic (fibrous interlocking); Cleavage: None (extremely tough); Specific gravity: 2.90-3.03
- Hardness
- 6
- Color
- Dark green to light grey-green
- Luster
- Greasy to waxy
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Physical properties
Hardness: 6.0-6.5 on Mohs scale; Color: Dark green to light grey-green; Luster: Greasy to waxy; Crystal structure: Monoclinic (fibrous interlocking); Cleavage: None (extremely tough); Specific gravity: 2.90-3.03
Formation & geological history
Formed through regional metamorphism of magnesium-rich rocks (ultramafic) in the presence of water. Most New Zealand nephrite formed during the Mesozoic era within the Southern Alps mountain-building processes.
Uses & applications
Used primarily in jewelry, traditional Maori carvings (Hei Matau), ornamental art, and historically for durable tools and weapons due to its extreme toughness.
Geological facts
Nephrite is actually tougher (more resistant to fracturing) than diamond because of its interlocking felt-like fibrous structure. In New Zealand, it is known as Pounamu or Greenstone and is considered a sacred treasure (Taonga) by the Maori people.
Field identification & locations
Identify by its waxy luster and extreme resistance to breakage. Found in riverbeds and coastal areas of the South Island, New Zealand (notably the West Coast and Otago). Collectors should look for translucency and lack of internal fractures.
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