Granite

**Granite Composition and Formation**:
– Granite is a coarse-grained intrusive igneous rock composed mainly of quartz, alkali feldspar, and plagioclase.
– The chemical composition of granite includes 72.04% silica, 14.42% alumina, and varying amounts of other elements.
– Granites are classified based on their mineral composition and percentages of quartz, alkali feldspar, and plagioclase.
– Granite forms from silica-rich magmas known as felsic magmas, which can be influenced by processes like fractional crystallization.
– True granites contain between 20% and 60% quartz by volume and are named based on the QAPF diagram for coarse-grained plutonic rocks.

**Occurrence and Geological Features of Granite**:
– Granitic rocks are widely distributed throughout the continental crust and are commonly found in igneous intrusions ranging from dikes to batholiths.
– Most granites were intruded during the Precambrian age and underlie the sedimentary veneer of continents.
– Granites occur in various forms like tors, domes, bornhardts, and rounded massifs, and are associated with orogenic mountain ranges.
– Granites are found in stock masses, batholiths, and may occur with pegmatite masses in some locations.
– The origin of granites can vary, with some forming from felsic magmas and others from fractional crystallization of basaltic magma.

**Uses and Significance of Granite**:
– Granite is widely used in construction for its hardness, toughness, and durability, making it suitable for various applications.
– Ancient civilizations like the Egyptians and Romans used granite in monumental architecture, temples, and pyramids.
– Modern uses of granite include countertops, flooring, monuments, sculptures, and road construction materials.
– Granite has cultural and historical significance, being present in structures like Buddhist shrines, medieval temples, and historical monuments worldwide.
– The granite industry is one of the oldest in the world, with major exporters including China, India, Italy, and the United States.

**Granite Weathering and Environmental Impact**:
– Granite undergoes physical and chemical weathering processes, leading to the formation of grus and influencing soil development.
– Weathering of granite can produce radon gas, which poses health risks when accumulated indoors.
– Some granites contain radioactive elements like uranium and thorium, impacting indoor air quality and potentially leading to lung cancer.
– Granite quarrying and processing can have environmental impacts, including habitat destruction and emissions of low levels of radiation from countertops.
– Climatic variations can influence the rate of granite weathering, affecting its longevity and permeability in pavements.

**Engineering and Industrial Applications of Granite**:
– Granite is extensively used in public and commercial buildings, with notable examples in Aberdeen, Scotland, and New England.
– In engineering, granite is used for surface plates, concrete substitutes, slabs, boulders for military purposes, and tramway tracks.
– The granite industry has evolved with modern cutting and carving methods, including computer-controlled tools and sandblasting techniques.
– Granite is used for paving due to its durability, low maintenance requirements, and permeability, commonly seen in urban settings.
– Granite’s engineering applications extend to the production of curling stones, rock climbing venues, and various industrial uses worldwide.https://en.wikipedia.org/wiki/Granite