metamorphic
Nuummite
Orthoamphibole (Gedrite-Anthophyllite series)
Hardness: 5.5-6.0 Mohs; Color: Black with iridescent flecks of gold, blue, or red; Luster: Vitreous to sub-metallic; Crystal System: Orthorhombic; Specific Gravity: 2.85-3.57
- Hardness
- 5
- Color
- Black with iridescent flecks of gold, blue, or red
- Luster
- Vitreous to sub-metallic
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Physical properties
Hardness: 5.5-6.0 Mohs; Color: Black with iridescent flecks of gold, blue, or red; Luster: Vitreous to sub-metallic; Crystal System: Orthorhombic; Specific Gravity: 2.85-3.57
Formation & geological history
Formed through high-grade metamorphism of volcanic rocks, it is approximately 3 billion years old, making it one of the oldest rocks on Earth. It was originally discovered in the Nuuk region of Greenland.
Uses & applications
Primarily used in jewelry as cabochons, for ornamental carvings, and as a highly sought-after specimen for mineral collectors and metaphysical practitioners.
Geological facts
Nuummite was discovered in 1810 by the mineralogist K. L. Giesecke, but it wasn't scientifically defined until late in the 20th century. Its unique iridescence is caused by lamellar structures within the minerals.
Field identification & locations
Identify by its unique 'flash' of needle-like crystals against a dark background. It is almost exclusively found in the remote Nuuk area of Greenland, though similar material has been reported in Mauritania and Finland.
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