Petrology is a field of geology which focuses on the study of rocks and the conditions by which they form. There are three branches of petrology, corresponding to the three types of rocks: igneous, metamorphic, and sedimentary. The word petrology itself comes from the Greek word "petra", meaning rock. This article does not cite its references or sources. ... The rocky side of a mountain creek near Orosí, Costa Rica. ... Igneous rocks are formed when molten rock (magma) cools and solidifies, with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. ... Metamorphic rock is the result of the transformation of a pre-existing rock type, the protolith, in a process called metamorphism, which means change in form, derived from the Greek words meta, change, and morphe, form. The protolith is subjected to extreme heat (>150 degrees Celsius) and pressure causing profound... Two types of sedimentary rock: limey shale overlaid by limestone. ...

• Igneous petrology focused on the composition and texture of igneous rocks (rocks such as granite or basalt which have crystallized from molten rock or magma). Igneous rocks include volcanic and plutonic rocks.
• Sedimentary petrology focuses on the composition and texture of sedimentary rocks (rocks such as sandstone or limestone which consist of sedimentary particles bound together in a matrix of finer material).
• Metamorphic petrology focuses on the composition and texture of metamorphic rocks (rocks such as slate or marble which started out as sedimentary or igneous rocks but which have undergone chemical, mineralogical or textural changes due to extremes of pressure, temperature or both).

Petrology utilizes the classical fields of mineralogy, microscopic petrography, and chemical analyses to describe the composition and texture of rocks. Modern petrologists also include the principles of geochemistry and geophysics through the studies of geochemical trends and cycles and the use of thermodynamic data and experiments to better understand the origins of rocks. Quarrying granite for the Mormon Temple, Utah Territory. ... Basalt Basalt is a common gray to black volcanic rock. ... Magma is molten rock located beneath the surface of the Earth (or any other rocky planet), and which often collects in a magma chamber. ... This article is about volcanoes in geology. ... Pluton redirects here. ... Red sandstone interior of Lower Antelope Canyon, Arizona, worn smooth due to erosion by flash flooding over millions of years Sandstone is a sedimentary rock composed mainly of sand-size mineral or rock grains. ... Limey shale overlaid by limestone. ... The matrix or groundmass of an igneous rock consists of fine grained often microscopic crystals in which larger crystals (phenocrysts) are embedded. ... Slate Slate is a fine-grained, homogeneous, metamorphic rock derived from an original sedimentary rock composed of clay or volcanic ash through low grade regional metamorphism. ... Venus de Milo, front. ... Mineralogy is an earth science that involves the chemistry, crystal structure, and physical (including optical) properties of minerals. ... Petrography is the description of rocks and their textures. ... The field of geochemistry involves study of the chemical composition of the Earth and other planets, chemical processes and reactions that govern the composition of rocks and soils, and the cycles of matter and energy that transport the Earths chemical components in time and space, and their interaction with... ‹ The template below has been proposed for deletion. ... Thermodynamics (Greek: thermos = heat and dynamic = change) is the physics of energy, heat, work, entropy and the spontaneity of processes. ...

Experimental petrology employs high-pressure, high-temperature apparatus to investigate the geochemistry and phase relations of natural or synthetic materials at elevated pressures and temperatures. Experiments are particularly useful for investigating rocks of the lower crust and upper mantle that rarely survive the journey to the surface in pristine condition. Earth cutaway from core to exosphere. ... Earth cutaway from core to exosphere. ...

See also

• Important publications in petrology