igneous
Granite countertop slab
Granite; primarily quartz, feldspar, and mica
AI-generated identification · may be incorrectCoarse-grained, speckled cream, gray, brown, and black appearance with vitreous quartz and feldspar luster; quartz hardness is 7, feldspar 6–6.5, and mica 2–3 Mohs. Interlocking crystals indicate an intrusive texture; cleavage occurs in feldspar and mica, not quartz.
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Physical properties
Coarse-grained, speckled cream, gray, brown, and black appearance with vitreous quartz and feldspar luster; quartz hardness is 7, feldspar 6–6.5, and mica 2–3 Mohs. Interlocking crystals indicate an intrusive texture; cleavage occurs in feldspar and mica, not quartz.
Formation & geological history
Slow cooling of silica-rich magma deep within Earth, generally during Precambrian to Phanerozoic plutonic events. The image shows a polished and likely sealed architectural slab rather than a natural hand specimen.
Uses & applications
Widely used for countertops, flooring, monuments, stairs, and decorative stone because of its hardness, durability, and heat resistance. Common commercial value is about $40–$150 per square foot installed, varying by rarity and fabrication.
Geological facts
Granite is not a single mineral but a coarse-grained rock defined by abundant quartz and alkali feldspar. Dark streaks or patches commonly represent biotite, hornblende, or mafic enclaves.
Field identification & locations
Identify it by visible interlocking crystals, abundant light feldspar/quartz, and scattered dark mica; unlike marble, it does not fizz readily with dilute acid. Common sources include Brazil, India, China, Canada, and the United States.
