igneous
Granite
Phaneritic Plutonic Rock (High Silica content)
Hardness: 6-7 on Mohs scale; Color: Grayish-white with salt and pepper speckling; Luster: Dull to vitreous; Crystal structure: Phaneritic (visible interlocking crystals of quartz, feldspar, and mica); Cleavage: None (fractures irregularly); Specific gravity: 2.65–2.75 g/cm³.
- Hardness
- 6-7 on Mohs scale
- Color
- Grayish-white with salt and pepper speckling
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Grayish-white with salt and pepper speckling; Luster: Dull to vitreous; Crystal structure: Phaneritic (visible interlocking crystals of quartz, feldspar, and mica); Cleavage: None (fractures irregularly); Specific gravity: 2.65–2.75 g/cm³.
Formation & geological history
Formed from the slow cooling of magma deep beneath the Earth's surface (intrusive igneous). It can date back billions of years to the Archean Eon or be as young as a few million years. Typically found in continental crust and mountain ranges.
Uses & applications
Extensively used in construction (countertops, floor tiles, paving stones), monuments, and as crushed stone for road base. Sometimes used for low-cost lapidary tumbling for hobbyists.
Geological facts
Granite is the most common rock in Earth's continental crust. It is the primary component of many famous mountain ranges, including the Sierra Nevada and the Himalayas. Due to its durability, it was used to build the Great Pyramid of Giza's inner chambers.
Field identification & locations
Identify by its interlocking 'mosaic' of minerals and lack of layering. It will not react with acid (unlike limestone) and can easily scratch glass. Commonly found in mountainous regions or as glacial erratic stones in gravel pits.
