Granite
Granite ( /ˈɡrænɨt/) is a common widely occurring type of intrusive, felsic, igneous rock which is granular and crystalline in texture. This rock consists mainly of quartz, mica, and feldspar. Occasionally some individual crystals (phenocrysts) are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic texture is sometimes known as a porphyry. Granites can be pink to gray in color, depending on their chemistry and mineralogy. By definition, granite is an igneous rock with at least 20% quartz by volume. Granite differs from granodiorite in that at least 35% of the feldspar in granite is alkali feldspar as opposed to plagioclase; it is the alkali feldspar that gives many granites a distinctive pink color. Outcrops of granite tend to form tors and rounded massifs. Granites sometimes occur in circular depressions surrounded by a range of hills, formed by the metamorphic aureole or hornfels. Granite is usually found in the continental plates of the Earth's crust.
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Famous quotes containing the word granite:
“We placed the wreaths upon the splended granite sarcophagus, and at its feet, and felt that only the earthly robe we loved so much was there. The pure, tender, loving spirit which loved us so tenderly, is above us—loving us, praying for us, and free from all suffering and woe—yes, that is a comfort, and that first birthday in another world must have been a far brighter one than any in this poor world below!”
—Victoria (1819–1901)
“Hell is paved with great granite blocks hewn from the hearts of those who said, “I can do no other.””
—Heywood Broun (1888–1939)
“For my part, I travel not to go anywhere, but to go. I travel for travel’s sake. The great affair is to move; to feel the needs and hitches of our life more nearly; to come down off this feather-bed of civilisation, and find the globe granite underfoot and strewn with cutting flints.”
—Robert Louis Stevenson (1850–1894)