graniitit

Graniitit are a family of coarse-grained felsic intrusive igneous rocks that crystallize from silica-rich magmas cooling slowly beneath the Earth’s surface. This slow cooling allows large mineral crystals to form, giving granites their characteristic visible grains and light overall color.

The essential minerals in graniitit are quartz and alkali feldspar, with plagioclase feldspar commonly present as well. Accessory minerals such as biotite, muscovite, hornblende, magnetite, and zircon may occur. The typical texture is holocrystalline and coarse-grained, though some varieties are porphyritic, featuring large feldspar phenocrysts within a finer-grained groundmass.

Graniitit form in continental crust where magmas differentiate or melt from existing rocks. They are commonly emplaced as batholiths or plutons and may be exposed at the surface after uplift and erosion. Their durable nature and resistance to weathering influence landscape development and soil formation.

Graniitit are widely used in construction and design due to their hardness and aesthetic appeal. They are quarried as dimension stone and crushed for use in buildings, monuments, and architectural features, as well as for countertops and decorative applications.

Globally, granitiin graniitit occur on every continent and constitute a significant portion of exposed continental crust in many mountain belts. They are a principal example of felsic intrusive rocks and provide important insights into crustal formation and tectonic processes.