igneous

Spinifex Textured Komatiite

Ultramafic Komatiite (with Olivine Spinifex)

Hardness: 6-7 (Mohs scale); Color: Dark grey to greenish-black; Luster: Dull to vitreous; Crystal structure: Contains distinctive long, needle-like or blade-like crystals of olivine or pyroxene arranged in a criss-cross pattern; Specific Gravity: 3.0-3.4

Hardness: 6-7 (Mohs scale)
Color: Dark grey to greenish-black
Luster: Dull to vitreous

Identified April 7, 2026More igneous →

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Physical properties

Formation & geological history

Formed from extremely high-temperature (over 1600°C) lava flows with low viscosity, primarily during the Archean Eon (over 2.5 billion years ago). The spinifex texture results from rapid cooling and crystallization of olivine at the top of lava flows.

Uses & applications

Primarily used for geological research to understand the Earth's early mantle. They are also vital economic indicators as they often host major nickel-copper-platinum group element (PGE) sulfide deposits.

Geological facts

Named after the Australian 'spinifex' grass because the crystal patterns resemble the grass's spiky blades. Komatiites are rare because the Earth's mantle has cooled significantly since the Archean, making these types of volcanic eruptions nearly impossible today.

Field identification & locations

Identify by the unique 'matchstick' or criss-cross bladed pattern on the weathered surface. Commonly found in ancient 'greenstone belts' such as the Barberton belt in South Africa, the Abitibi belt in Canada, and the Yilgarn Craton in Western Australia.

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