Granite

Hardness: 6-7 on Mohs scale. Color: Variable, often pink, red, white, gray, or black, depending on mineral composition. Luster: Vitreous to sub-vitreous. Crystal Structure: Granular, phaneritic texture (visible crystals). No distinct cleavage planes for the rock as a whole.

Formed from the slow crystallization of magma beneath the Earth's surface. It is an intrusive igneous rock, meaning it cooled and solidified within the Earth's crust. Its geological age varies widely, often found in ancient Precambrian shields and younger orogenic belts. It forms in large plutons, batholiths, and dikes.

Industry: Widely used as a construction material for buildings, bridges, monuments, and gravestones due to its strength and resistance to weathering. Interior use: Countertops, floor tiles, and decorative panels. Jewelry/Art: Occasionally polished and used for ornamental objects, but not typically cut as a gemstone.

Granite is one of the most abundant intrusive igneous rocks in the Earth's continental crust. Many famous natural landmarks (e.g., Yosemite's Half Dome, Mount Rushmore) and ancient structures are carved from or built with granite. Its durability and aesthetic appeal have made it a classic building material for centuries.

Field Identification: Look for a coarse-grained, interlocking crystalline texture with visible grains of quartz (glassy, gray), feldspar (white, pink, or red), and darker minerals like biotite mica (black flakes) or hornblende (black elongated crystals). The color variation is key. Common Locations: Found globally in continental crust, particularly in mountain ranges and stable cratonic areas (e.g., Sierra Nevada (USA), Appalachian Mountains (USA), Scandinavian Shield). Tips for Collectors: Its hardness and resistance to weathering mean it can be found as well-preserved boulders or river pebbles. Look for the distinct intergrowth of different colored mineral grains.