igneous
Crushed Granite Gravel
Granite (composed primarily of Quartz, Alkali Feldspar, and Plagioclase Feldspar)
Hardness: 6-7 Mohs; Color: Salt and pepper (pink, gray, white, and black); Luster: Dull to vitreous; Crystal Structure: Phaneritic (coarse-grained); Cleavage: Imperfect; Specific Gravity: 2.63-2.75
- Hardness
- 6-7 Mohs
- Color
- Salt and pepper (pink, gray, white, and black)
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6-7 Mohs; Color: Salt and pepper (pink, gray, white, and black); Luster: Dull to vitreous; Crystal Structure: Phaneritic (coarse-grained); Cleavage: Imperfect; Specific Gravity: 2.63-2.75
Formation & geological history
Formed by the slow cooling of magma deep beneath the Earth's surface (plutonic formation), typically during Orogeny events millions of years ago. These specific specimens are mechanically crushed and screened from larger quarry deposits.
Uses & applications
Extensively used in construction for road base, railway ballast, concrete aggregate, decorative landscaping, and driveways.
Geological facts
Granite is the most common rock type found in the Earth's continental crust. It is so durable that it was used by Ancient Egyptians to build temples and line the insides of the Great Pyramid of Giza.
Field identification & locations
Identify in the field by its speckled 'salt and pepper' appearance and visible interlocking crystals. Common in mountainous regions or shield areas like the Canadian Shield. For collectors, look for versions with high potassium feldspar content for a deep pink/red color.
