Granite

Physical Properties

Hardness: 6-7 Mohs; Color: Pink, light gray, white with black specks; Luster: Vitreous to dull; Crystal structure: Phaneritic (coarse-grained); Cleavage: Uneven/none; Specific Gravity: 2.63-2.75

Formation & Geological History

Formed by the slow crystallization of magma below Earth's surface. It is a coarse-grained intrusive rock common in continental crusts and mountain ranges. It can be found in a wide variety of geological ages ranging from the Precambrian to recent periods.

Uses & Applications

Extensively used in construction for countertops, floor tiles, paving stones, monuments, and as aggregate in infrastructure projects.

Geological Facts

Granite is one of the hardest and most durable rocks on Earth. It makes up a large part of the continental crust and is famous for forming landmarks like Yosemite's Half Dome and Mount Rushmore.

Field Identification & Locations

Identified by its visible interlocking crystals of quartz, feldspar, and dark minerals (like biotite or hornblende). It is commonly found in batholiths and shield areas of continents. Collectors look for unique colors or accessory minerals.

Identified on: 5/4/2026

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