igneous
Porphyritic granite or granitic pegmatite
Coarse-grained felsic intrusive rock, principally quartz, alkali feldspar, plagioclase, and biotite/hornblende
AI-generated identification · may be incorrectLight tan to pink, with visible pale feldspar and dark mica/amphibole crystals in a coarse, porphyritic texture; vitreous quartz and uneven fracture. Typical hardness is about 6–7 Mohs and specific gravity 2.6–2.7.
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Physical properties
Light tan to pink, with visible pale feldspar and dark mica/amphibole crystals in a coarse, porphyritic texture; vitreous quartz and uneven fracture. Typical hardness is about 6–7 Mohs and specific gravity 2.6–2.7.
Formation & geological history
Formed by slow cooling and crystallization of silica-rich magma deep in the crust, likely millions to billions of years ago; later exposed by uplift and erosion. The image may also show weathering and iron staining along fractures.
Uses & applications
Used as dimension stone, building aggregate, monuments, countertops, and landscaping rock; attractive pieces are collected but generally have modest specimen value.
Geological facts
The large crystals indicate prolonged cooling, while the irregular dark grains are likely biotite or hornblende. Pink coloration commonly comes from potassium feldspar and iron oxidation.
Field identification & locations
Identify it by its interlocking visible crystals, hard fresh surfaces, and lack of layering or vesicles; a glassy quartz grain and feldspar cleavage help confirm granite. Common worldwide in continental mountain belts and exposed shields.
