igneous
Granite Water-Worn Pebble
Phaneritic Felsic Igneous Rock
Hardness: 6-7 on Mohs scale. Color: Mottled pink, grey, and black. Luster: Vitreous to dull. Crystal Structure: Phaneritic (visible crystals of quartz, feldspar, and mica). Specific Gravity: 2.63-2.75.
- Hardness
- 6-7 on Mohs scale
- Color
- Mottled pink, grey, and black
- Luster
- Vitreous to dull
Identified More igneous →
Explore Granite Water-Worn Pebble 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: Mottled pink, grey, and black. Luster: Vitreous to dull. Crystal Structure: Phaneritic (visible crystals of quartz, feldspar, and mica). Specific Gravity: 2.63-2.75.
Formation & geological history
Formed by the slow cooling of silica-rich magma deep underground, typically during the Precambrian or Paleozoic eras. This specific specimen has been rounded and smoothed by water erosion in a river or beach environment.
Uses & applications
Larger deposits are used for countertops, construction, and monuments. Small pebbles are used for landscaping, decorative aquariums, and rock tumbling hobbies.
Geological facts
Granite makes up a large portion of the Earth's continental crust. The pink color in this specimen is specifically caused by Potassium Feldspar (Orthoclase).
Field identification & locations
Identify by the 'salt and pepper' appearance and visible interlocking crystals. Common in glacial till and riverbeds across North America and Europe. Look for a mix of translucent quartz and opaque feldspar.
