Granite

Hardness: 6-7 on Mohs scale (due to quartz and feldspar). Color: Highly variable, often white, gray, pink, or red, with dark specks. The visible specimen has a dark brown/reddish-brown background with lighter (likely feldspar or quartz) and darker (likely biotite or hornblende) flecks. Luster: Vitreous to glassy. Crystal Structure: Phaneritic (coarse-grained), interlocking crystals. Generally exhibits no cleavage as a whole rock, though constituent minerals have cleavage.

Formed from the slow crystallization of magma below Earth's surface (intrusive igneous). It's a key component of continental crust. Formation typically occurs deep within the crust, often associated with orogenic events (mountain building) or continental rifting. Geological age varies widely, from Precambrian to Cenozoic.

Widely used as an architectural and dimensional stone for building facades, floor tiles, paving stone, monuments, and countertops due to its durability, aesthetic appeal, and resistance to weathering. Also used as crushed stone for road aggregate and railway ballast. Its beautiful patterns and ability to take a high polish make it popular for decorative purposes.

Granite is one of the most common intrusive igneous rocks. The term 'granite' is often used commercially for any feldspar-bearing igneous rock, or even some metamorphic rocks with a granular texture. True geological granite is very specific in its mineral composition. It's known for its durability and has been used in construction for thousands of years, from ancient Egyptian pyramids to modern skyscrapers. The specific variety in the image, with its dark reddish-brown color, is often sold commercially as 'Tan Brown Granite' or 'Baltic Brown Granite', which are popular choices for countertops.

Identify in the field by its coarse-grained, interlocking texture (phaneritic), visible minerals (typically quartz, feldspar, micas, and amphiboles), and light to dark color range. It often forms large batholiths or stocks. Commonly found in continental crust, particularly in mountain ranges and stable cratonic areas worldwide. For collectors, granite itself is less collected than individual mineral specimens within it, but polished slabs are popular for their aesthetic appeal. In the field, look for outcrops that show its massive, blocky nature and resist erosion more than surrounding softer rocks.