Granite

Medium-grained, gray to pink, speckled appearance with interlocking crystals; Mohs hardness 6–7, vitreous quartz luster, poor cleavage as a whole, and specific gravity about 2.63–2.75.

A coarse-grained intrusive igneous rock formed by slow cooling of silica-rich magma deep in the crust, commonly during Precambrian to Phanerozoic plutonic events.

Widely used for countertops, monuments, building cladding, paving, aggregate, and occasionally polished decorative specimens; ordinary pieces have little collector value.

Its visible granular texture records slow underground crystallization. Dark grains are typically biotite or amphibole, while translucent grains are quartz.

Identify it by its interlocking visible crystals, abundant quartz, and lack of layering or foliation; common worldwide, especially in continental shields and mountain batholiths. A scratch, fresh surface, or dilute acid test helps distinguish it from limestone, which effervesces.