igneous
Granite cobble
Granite; coarse-grained quartz–feldspar–mica rock
AI-generated identification · may be incorrectLight pinkish-gray, speckled texture with visible quartz and feldspar; likely Mohs 6–7, vitreous to dull luster, interlocking crystals, no prominent cleavage as a whole, and specific gravity about 2.6–2.7.
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Physical properties
Light pinkish-gray, speckled texture with visible quartz and feldspar; likely Mohs 6–7, vitreous to dull luster, interlocking crystals, no prominent cleavage as a whole, and specific gravity about 2.6–2.7.
Formation & geological history
An intrusive igneous rock crystallized slowly from silica-rich magma several kilometers underground, commonly during Precambrian to Phanerozoic continental magmatism; the rounded shape indicates transport or landscaping use.
Uses & applications
Widely used for construction aggregate, curbs, monuments, countertops, paving, and dimension stone; this small specimen has mainly educational or decorative value.
Geological facts
Its pink color commonly comes from potassium feldspar, while dark flecks are biotite or amphibole. Individual mineral grains are usually visible without magnification.
Field identification & locations
Identify it by coarse interlocking grains, pale quartz, pink/white feldspar, and black mica; unlike sandstone, it lacks cemented layers or sand grains. Common worldwide, especially in continental shields and mountain belts.
