igneous
Granite and Igneous Mix
Phaneritic Felsic to Mafic Intrusive Rocks
Hardness: 6-7 Mohs; Color: Pink, grey, white, and black; Luster: Vitreous to dull; Crystal structure: Phaneritic (visible crystals); Composition: Quartz, Feldspar, Mica, and Hornblende.
- Hardness
- 6-7 Mohs
- Color
- Pink, grey, white, and black
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6-7 Mohs; Color: Pink, grey, white, and black; Luster: Vitreous to dull; Crystal structure: Phaneritic (visible crystals); Composition: Quartz, Feldspar, Mica, and Hornblende.
Formation & geological history
Formed from the slow cooling of silica-rich magma deep within the Earth's crust (plutonic). These specimens likely represent various stages of cooling and mineral assembly in continental crust environments.
Uses & applications
Commonly used in construction (countertops, flooring), road aggregates, monuments, and as decorative landscaping stones.
Geological facts
Granite makes up a large portion of the Earth's continental crust. Unlike oceanic crust which is primarily basalt, continents are largely composed of these lighter, silica-rich igneous rocks.
Field identification & locations
Identify by the 'salt and pepper' appearance of interlocking crystals. Look for the glint of mica flakes and the hardness (won't be scratched by a steel knife). Commonly found in mountainous regions or glacial till.
