metamorphic
Nuummite
Nuummite (Orthoamphibole rock composed of Anthophyllite and Gedrite)
Hardness: 5.5-6.0 on Mohs scale; Color: Black to dark brown with iridescent flashes (labradorescence) of gold, blue, or green; Luster: Vitreous to sub-metallic; Crystal structure: Orthorhombic; Specific Gravity: 2.85-3.57.
- Hardness
- 5
- Luster
- Vitreous to sub-metallic
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Physical properties
Hardness: 5.5-6.0 on Mohs scale; Color: Black to dark brown with iridescent flashes (labradorescence) of gold, blue, or green; Luster: Vitreous to sub-metallic; Crystal structure: Orthorhombic; Specific Gravity: 2.85-3.57.
Formation & geological history
Formed approximately 3 billion years ago (Archean age) through high-grade metamorphism. It is one of the oldest volcanic rocks on Earth, originally formed as an igneous rock that was later subjected to heat and pressure to create its unique fibrous structure.
Uses & applications
Primarily used for lapidary work, including cabochons, beads, and polished spheres. It is highly valued by collectors and the metaphysical community for its age and rare iridescent properties.
Geological facts
Nuummite was discovered in 1982 near Nuuk, Greenland. Because of the harsh Arctic climate, it can only be mined during the few months of the year when the ground is not frozen.
Field identification & locations
Identify in the field by searching for 'schiller' or flashes of color within a dark, dense matrix. It is found almost exclusively in the Nuuk region of Greenland, though similar material has been reported in Finland and Norway. Collectors should look for the unique lamellar structure that causes the light to refract.
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