Granite (Orthoclase rich)

Physical Properties

Hardness: 6-7 (Mohs scale); Color: Pinkish-orange with green/grey hints; Luster: Vitreous to pearly; Crystal structure: Phaneritic (coarse-grained) igneous; Cleavage: Two directions at 90 degrees (for feldspar component); Specific gravity: 2.63 - 2.75

Formation & Geological History

Formed from the slow crystallization of magma below Earth's surface. This intrusive process allows for the growth of visible mineral crystals. Most granites formed during the Phanerozoic and Proterozoic eons.

Uses & Applications

Used extensively in construction for countertops, floor tiles, paving stone, curbing, and monuments. Also a primary source for mineral specimens for students and collectors.

Geological Facts

Granite constitutes a large part of the continental crust. The pink color in this specimen is specifically due to a high concentration of orthoclase, a potassium-rich feldspar.

Field Identification & Locations

Identify in the field by its speckled, coarse appearance and its inability to be scratched by a steel knife. It is common in mountain ranges and shields like the Canadian Shield or the Appalachians.

Identified on: 4/19/2026

Mode: Standard