igneous
Red granite or weathered granitic rock
Granite, likely biotite–K-feldspar granite; exact identification requires testing
AI-generated identification · may be incorrectCoarse-grained, crystalline texture with reddish potassium feldspar, gray quartz, dark biotite/amphibole, and possible iron-oxide weathering. Typical hardness is about 6–7 Mohs, nonmetallic luster, massive structure, and poor or absent cleavage as a whole rock.
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Physical properties
Coarse-grained, crystalline texture with reddish potassium feldspar, gray quartz, dark biotite/amphibole, and possible iron-oxide weathering. Typical hardness is about 6–7 Mohs, nonmetallic luster, massive structure, and poor or absent cleavage as a whole rock.
Formation & geological history
An intrusive igneous rock that crystallized slowly from silica-rich magma deep underground, commonly during Precambrian to Phanerozoic continental activity; surface oxidation and weathering produce the rusty red-brown colors.
Uses & applications
Crushed granite is used for aggregate, road stone, and construction; sound, attractive material is used for countertops, monuments, facing stone, and landscaping. This irregular specimen has modest collector value.
Geological facts
The red color generally comes from iron-bearing oxidation in feldspar or fractures rather than from a separate red mineral. Dark patches may reflect biotite, hornblende, or weathered mafic inclusions.
Field identification & locations
Look for visible interlocking crystals, pink/red feldspar, translucent gray quartz, and black mica; a steel knife should not easily scratch fresh quartz. Common worldwide in continental shields and granite batholiths; a streak, acid, and thin-section test would refine the ID.
