igneous
Granite (with Quartz and Mica)
Phaneritic Felsic Igneous Rock
Hardness: 6-7 (Mohs); Color: Mottled white, grey, and reddish-brown; Luster: Vitreous to pearly; Structure: Phaneritic (coarse-grained); Cleavage: Poor; Specific Gravity: 2.63 to 2.75
- Hardness
- 6-7 (Mohs)
- Color
- Mottled white, grey, and reddish-brown
- Luster
- Vitreous to pearly
Identified More igneous →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 (Mohs); Color: Mottled white, grey, and reddish-brown; Luster: Vitreous to pearly; Structure: Phaneritic (coarse-grained); Cleavage: Poor; Specific Gravity: 2.63 to 2.75
Formation & geological history
Formed through the slow cooling and crystallization of silica-rich magma deep within the Earth's crust (plutonic formation). These rocks typically date back to the Precambrian or Paleozoic eras when mountain-building events occurred.
Uses & applications
Extensively used in construction for countertops, floor tiles, and curbing. In industry, it is used as crushed stone for road base. Specimens with distinct crystal clusters are popular for mineral collecting and paperweights.
Geological facts
Granite is the most common rock found in the continental crust and forms the core of many mountain ranges. Mount Rushmore is carved into a massive granite batholith in the Black Hills of South Dakota.
Field identification & locations
Identify in the field by its 'salt and pepper' appearance and visible interlocking crystals of quartz (clear/grey) and feldspar (white/pink). Look for the reflective flashes of mica flakes. Common in mountainous regions and glacial deposits.
More like this
Other igneous specimens
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Dark Igneous Rock (Likely Basalt or Diabase)
Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.
Igneous
Magnetite
Iron(II,III) oxide (Fe3O4)
mineral
Sodalite
Sodalite - Na8(Al6Si6O24)Cl2
mineral
Blue Apatite
Apatite (Group), Ca5(PO4)3(F,Cl,OH)
mineral
Magnetite
Magnetite (Fe3O4)
mineral