igneous
Granite
Granite; chiefly quartz, alkali feldspar, plagioclase, and mica
AI-generated identification · may be incorrectCoarse-grained, speckled gray-pink rock with a granular texture and vitreous-to-dull luster. Hardness is about 6–7 Mohs; crystals are interlocking, with no dominant cleavage as a whole, and specific gravity is roughly 2.63–2.75.
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Physical properties
Coarse-grained, speckled gray-pink rock with a granular texture and vitreous-to-dull luster. Hardness is about 6–7 Mohs; crystals are interlocking, with no dominant cleavage as a whole, and specific gravity is roughly 2.63–2.75.
Formation & geological history
An intrusive igneous rock formed when silica-rich magma cooled slowly deep underground, allowing visible crystals to grow. Its exact geological age cannot be determined from the image; granite ranges from Archean to recent ages.
Uses & applications
Widely used for countertops, paving, monuments, building stone, aggregate, and landscaping; attractive polished pieces are also collected. This specimen appears common and has little commercial value.
Geological facts
The granular texture is called phaneritic, reflecting slow cooling. Pink areas commonly represent potassium feldspar, while dark grains are typically biotite or hornblende.
Field identification & locations
Identify it by visible interlocking quartz and feldspar crystals, gray-pink coloration, and a hard, crystalline surface; it should not fizz with dilute acid. Common worldwide, especially in continental shields and mountain batholiths.
