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.
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.
Geology - Earth Composition, Rocks, Minerals | Britannica
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
mineral - Students | Britannica Kids | Homework Help
The science of mineralogy is concerned with the minerals that make up the rocks, clays, sand, and similar materials of the Earth. Mineralogy includes the study of the physical and chemical properties of minerals, their forms, and the various ways in …
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).
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.
rock - Students | Britannica Kids | Homework Help
Most rocks contain several types of minerals; for example, the igneous rock granite is largely composed of the minerals quartz, feldspar, and mica. In contrast, pure sandstone, a sedimentary rock, contains only the mineral quartz.
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 ...
Geology - Geochemistry, Rocks, Minerals | Britannica
Organic chemical reactions influence many geochemical processes, as, for example, rock weathering and production of soil, the solution, precipitation, and secretion of such dissolved materials as calcium carbonate, and the alteration of sediments to form sedimentary rocks.