igneous
Granite
Intrusive Felsic Igneous Rock
Hardness: 6-7 on Mohs scale. Color: Pinkish-red, white, gray, and black speckled matrix. Luster: Dull to vitreous. Texture: Phaneritic (medium to coarse-grained mineral grains). Composition: Potassium feldspar, quartz, plagioclase feldspar, and biotite mica/amphibole.
- Hardness
- 6-7 on Mohs scale
- Color
- Pinkish-red, white, gray, and black speckled matrix
- Luster
- Dull to vitreous
Identified More igneous →
Explore Granite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 on Mohs scale. Color: Pinkish-red, white, gray, and black speckled matrix. Luster: Dull to vitreous. Texture: Phaneritic (medium to coarse-grained mineral grains). Composition: Potassium feldspar, quartz, plagioclase feldspar, and biotite mica/amphibole.
Formation & geological history
Formed by the slow crystallization of silica-rich magma deep underground beneath continental crust over millions of years. This rounded pebble has undergone water or glacial erosion.
Uses & applications
Widely used in construction, dimension stone, kitchen countertops, paving, monument carving, and as crushed aggregate. Smooth river pebbles are popular for landscaping and decorative collections.
Geological facts
Granite makes up a large portion of the Earth's continental crust. The pink color in this specimen comes from orthoclase (potassium) feldspar, while the clear/white areas are quartz and the dark specks are biotite or hornblende.
Field identification & locations
Identified by its speckled 'salt and pepper' appearance with pinkish hues, coarse interlocking mineral crystals, and high hardness (scratches glass). Common in riverbeds, glacial deposits, beaches, and mountainous regions worldwide.
