igneous
Spinifex Textured Komatiite
Ultramafic Komatiite
Hardness: 6-7 (on Mohs scale); Color: Dark grey to greenish-black; Luster: Dull to sub-metallic; Crystal structure: Acicular/bladed olivine or pyroxene crystals; Specific gravity: 3.0-3.4
- Hardness
- 6-7 (on Mohs scale)
- Color
- Dark grey to greenish-black
- Luster
- Dull to sub-metallic
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Physical properties
Hardness: 6-7 (on Mohs scale); Color: Dark grey to greenish-black; Luster: Dull to sub-metallic; Crystal structure: Acicular/bladed olivine or pyroxene crystals; Specific gravity: 3.0-3.4
Formation & geological history
Formed from extremely high-temperature (over 1600°C) ultramafic lava flows that cooled rapidly at the surface. These are primarily found in Archean greenstone belts, dating back 2.5 to 3.8 billion years.
Uses & applications
Primarily used for geological research and as a key indicator for nickel-copper-platinum group element (PGE) sulfide deposits in mining exploration.
Geological facts
The 'Spinifex' texture is named after a spiky Australian grass because the long, bladed crystals resemble its growth pattern. These lavas were so hot they could flow like water and even melt the ground beneath them.
Field identification & locations
Identify by looking for long, radiating, or criss-crossing bladed crystal patterns in dark volcanic rock. Often found in Western Australia, Canada (Abitibi belt), and South Africa (Barberton).
