igneous
Granite Pebble
Granite (Phaneritic intrusive igneous rock)
Hardness: 6-7 on Mohs scale. Color: Salt-and-pepper appearance with grey, black, and white grains. Luster: Dull to vitreous. Crystal structure: Phaneritic (visible crystals). Specific gravity: 2.63 to 2.75.
- Hardness
- 6-7 on Mohs scale
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6-7 on Mohs scale. Color: Salt-and-pepper appearance with grey, black, and white grains. Luster: Dull to vitreous. Crystal structure: Phaneritic (visible crystals). Specific gravity: 2.63 to 2.75.
Formation & geological history
Formed from the slow crystallization of magma below Earth's surface. High in silica and alkali metals. Can be billions of years old, typically found in continental crust.
Uses & applications
Used extensively in construction, countertops, monuments, and as crushed stone for road base. Smooth pebbles are often used in landscaping and decorative gardening.
Geological facts
Granite is the most common igneous rock found on Earth's continents. It is so durable that the Great Pyramid of Giza contains huge blocks of it in the King's Chamber.
Field identification & locations
Identify by its 'speckled' appearance caused by interlocking crystals of quartz, feldspar, and mica. Commonly found in riverbeds, glacial tills, and mountainous regions.
