Rock | Definition, Characteristics, Formation, Cycle, Classification ...
2024年10月22日 · Rock, in geology, naturally occurring and coherent aggregate of one or more minerals. Such aggregates constitute the basic unit of which the solid Earth is composed and typically form recognizable and mappable volumes. The three major classes of rock are igneous, sedimentary, and metamorphic rock.
Mineral | Types & Uses | Britannica
2024年11月12日 · Mineral, naturally occurring homogeneous solid with a definite chemical composition and a highly ordered atomic arrangement. Usually formed by inorganic processes, there are several thousand known mineral species, about 100 of which constitute the major mineral components of rocks.
Sedimentary rock | Definition, Formation, Examples,
2024年10月30日 · sedimentary rock, rock formed at or near Earth’s surface by the accumulation and lithification of sediment (detrital rock) or by the precipitation from solution at normal surface temperatures (chemical rock).
Metamorphic rock | Definition, Formation, & Facts | Britannica
2024年11月23日 · metamorphic rock, any of a class of rocks that result from the alteration of preexisting rocks in response to changing environmental conditions, such as variations in temperature, pressure, and mechanical stress, and the …
Rock - Structure, Texture, Composition | Britannica
2024年10月22日 · Since rocks are aggregates of mineral grains or crystals, their properties are determined in large part by the properties of their various constituent minerals. In a rock these general properties are determined by averaging the relative properties and sometimes orientations of the various grains or crystals.
Igneous rock | Characteristics, Examples, Formation, & Types
2024年11月12日 · igneous rock, any of various crystalline or glassy rocks formed by the cooling and solidification of molten earth material. Igneous rocks constitute one of the three principal classes of rocks, the others being metamorphic and sedimentary.
Mineral - Occurrence, Formation, Compound | Britannica
2024年11月12日 · The four main categories of mineral formation are: (1) igneous, or magmatic, in which minerals crystallize from a melt, (2) sedimentary, in which minerals are the result of sedimentation, a process whose raw materials are particles from other rocks that have undergone weathering or erosion, (3) metamorphic, in which new minerals form at the ...
Igneous rock - Minerals, Magma, Crystals | Britannica
2024年11月12日 · Igneous rock - Minerals, Magma, Crystals: The major mineralogical components of igneous rocks can be divided into two groups: felsic (from feldspar and silica) and mafic (from magnesium and ferrous iron).
Geology | Definition, Examples, Rocks, Study, Importance, & Facts ...
2024年10月4日 · An introduction to the geochemical and geophysical sciences logically begins with mineralogy, because Earth’s rocks are composed of minerals—inorganic elements or compounds that have a fixed chemical composition and that …
Geology - Earth Composition, Rocks, Minerals | Britannica
2024年10月4日 · About 3,000 distinct mineral species are recognized, but relatively few are important in the kinds of rocks that are abundant in the outer part of the Earth. Thus a few minerals such as the feldspars, quartz, and mica are