igneous
Granite Pebble
Felsic Intrusive Igneous Rock
Hardness: 6-7 (Mohs scale); Color: Mottled pink, white, and black; Luster: Vitreous to dull; Crystal structure: Phaneritic (visible crystals); Specific gravity: 2.63–2.75
- Hardness
- 6-7 (Mohs scale)
- Color
- Mottled pink, white, and black
- Luster
- Vitreous to dull
Identified More igneous →
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Physical properties
Hardness: 6-7 (Mohs scale); Color: Mottled pink, white, and black; Luster: Vitreous to dull; Crystal structure: Phaneritic (visible crystals); Specific gravity: 2.63–2.75
Formation & geological history
Formed from the slow cooling and crystallization of magma beneath the Earth's surface (plutonic). This sample likely eroded and was smoothed by water transport.
Uses & applications
Used in construction, countertops, monuments, and as crushed aggregate. Small pebbles are often used in landscaping or for drainage.
Geological facts
Granite makes up much of the Earth's continental crust. It contains quartz, feldspar, and mica. The pink color in this specimen is likely due to potassium feldspar (orthoclase).
Field identification & locations
Identify in the field by its 'salt and pepper' appearance and hardness (it will scratch glass). Common in mountain ranges and riverbeds downstream from igneous deposits.
