igneous
Granite Pebble
Granite (Felsic Plutonic Rock)
Hardness: 6-7 on Mohs scale. Color: Mottled orange-red (potassium feldspar), grey/clear (quartz), and black (biotite/hornblende). Luster: Dull to vitreous. Crystal structure: Phaneritic (coarse-grained crystals). Cleavage: Two directions for feldspar, none for quartz. Specific gravity: 2.63 to 2.75.
- Hardness
- 6-7 on Mohs scale
- Luster
- Dull to vitreous
Identified More igneous →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 on Mohs scale. Color: Mottled orange-red (potassium feldspar), grey/clear (quartz), and black (biotite/hornblende). Luster: Dull to vitreous. Crystal structure: Phaneritic (coarse-grained crystals). Cleavage: Two directions for feldspar, none for quartz. Specific gravity: 2.63 to 2.75.
Formation & geological history
Formed from the slow cooling of magma deep beneath the Earth's surface (plutonic). This speciman has been weathered and rounded into a pebble, likely by water transport. Ages can range from millions to billions of years old.
Uses & applications
In bulk: construction, countertops, monuments, and gravel. Small pebbles like this are used in landscaping, aquariums, or as simple curiosities.
Geological facts
Granite makes up much of the Earth's continental crust. The pink or orange color in this specimen comes from orthoclase (potassium) feldspar.
Field identification & locations
Identify by its interlocking 'salt and pepper' or multi-colored crystalline texture and its extreme hardness. They are commonly found in riverbeds, glacial deposits, and mountainous regions worldwide.
