igneous
Pegmatitic granite, possibly potassium-feldspar-rich
Coarse-grained granite; mainly quartz (SiO₂), potassium feldspar (KAlSi₃O₈), plagioclase, and biotite/hornblende
AI-generated identification · may be incorrectHardness about 6–7; mottled salmon-pink, gray, black, and rusty-brown, with a coarse interlocking crystal texture and vitreous to pearly luster. Cleavage is prominent in feldspar but absent in quartz; approximate specific gravity 2.6–2.7.
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Physical properties
Hardness about 6–7; mottled salmon-pink, gray, black, and rusty-brown, with a coarse interlocking crystal texture and vitreous to pearly luster. Cleavage is prominent in feldspar but absent in quartz; approximate specific gravity 2.6–2.7.
Formation & geological history
A slowly cooled intrusive igneous rock formed from magma deep in the crust, likely during a late-stage granitic or pegmatitic intrusion. Its exact geological age cannot be determined from the image and depends on locality.
Uses & applications
Granite is widely used as building stone, aggregate, paving, monuments, and countertops; attractive pieces are collected as mineral specimens. This small, weathered fragment has little commercial value.
Geological facts
The salmon color commonly comes from potassium feldspar, while dark grains are mafic minerals and glassy gray areas are quartz. Rusty surfaces may reflect oxidation of iron-bearing minerals.
Field identification & locations
Identify it by visible interlocking quartz, feldspar, and dark mineral grains; it should not fizz with dilute hydrochloric acid and should scratch glass. Common worldwide in continental shield and mountain-belt intrusions.
