igneous
Granite / Quartzite Specimen
Granite / Quartz (SiO2 with Feldspar and Mica)
Hardness: 6-7 on Mohs scale; Color: Gray, beige, translucent quartz patches, and dark mica flecks; Luster: Vitreous to dull; Crystal structure: Coarse-grained phaneritic or granular aggregate; Specific gravity: ~2.65-2.75.
- Hardness
- 6-7 on Mohs scale
- Luster
- Vitreous to dull
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Gray, beige, translucent quartz patches, and dark mica flecks; Luster: Vitreous to dull; Crystal structure: Coarse-grained phaneritic or granular aggregate; Specific gravity: ~2.65-2.75.
Formation & geological history
Formed from the slow cooling and crystallization of felsic magma deep below Earth's surface in continental crust setting.
Uses & applications
Commonly used as crushed stone in construction, decorative gravel, landscape rock, and as an introductory rock sample for geology educational kits.
Geological facts
Granite makes up a large portion of Earth's continental crust and is composed primarily of quartz, feldspar, and biotite or muscovite mica.
Field identification & locations
Identify by its multi-mineral interlocking granular texture showing glassy quartz and pearly or dull feldspar/mica grains. Very common in mountainous terrain, riverbeds, and gravel deposits.
