igneous
Granite Pebble
Felsic Intrusive Igneous Rock
Hardness: 6-7 on Mohs scale; Color: Mottled pink, white, grey, and black; Luster: Dull to vitreous; Crystal Structure: Phaneritic (visible crystals of quartz, feldspar, and mica); Specific Gravity: 2.63 to 2.75
- Hardness
- 6-7 on Mohs scale
- Color
- Mottled pink, white, grey, and black
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6-7 on Mohs scale; Color: Mottled pink, white, grey, and black; Luster: Dull to vitreous; Crystal Structure: Phaneritic (visible crystals of quartz, feldspar, and mica); Specific Gravity: 2.63 to 2.75
Formation & geological history
Formed from the slow cooling of silica-rich magma deep underground. These pebbles are typically eroded from large plutonic bodies and rounded by river or glacial transport over thousands of years.
Uses & applications
Granite is used extensively in construction (countertops, flooring), monuments, and as crushed stone for road base. This specific pebble is a common collector item or landscaping stone.
Geological facts
Granite makes up a large portion of the Earth's continental crust. It is extremely durable and resistant to weathering, which is why it often remains as rounded pebbles in streambeds long after other rocks have eroded.
Field identification & locations
Identify in the field by its 'salt and pepper' appearance and the presence of sparkling mica flakes. It is found globally in continental shields and mountain ranges. Collectors find them in riverbeds and glacial tills.
