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  2. Rock (geology) - Wikipedia

    en.wikipedia.org/wiki/Rock_(geology)

    Rocks are composed primarily of grains of minerals, which are crystalline solids formed from atoms chemically bonded into an orderly structure. [4]: 3 Some rocks also contain mineraloids, which are rigid, mineral-like substances, such as volcanic glass, [5]: 55, 79 that lack crystalline structure. The types and abundance of minerals in a rock ...

  3. Mineral - Wikipedia

    en.wikipedia.org/wiki/Mineral

    In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form. [1] [2] The geological definition of mineral normally excludes compounds that occur only in living organisms.

  4. List of rock types - Wikipedia

    en.wikipedia.org/wiki/List_of_rock_types

    Sylvinite – Sedimentary rock made of a mechanical mixture of sylvite and halite; Tillite – Till which has been indurated or lithified by burial; Travertine – Form of limestone deposited by mineral springs; Tufa – Porous limestone rock formed when carbonate minerals precipitate out of ambient temperature water

  5. Portal:Minerals - Wikipedia

    en.wikipedia.org/wiki/Portal:Minerals

    A rock may consist of one type of mineral or may be an aggregate of two or more different types of minerals, spacially segregated into distinct phases. Some natural solid substances without a definite crystalline structure, such as opal or obsidian, are more properly called mineraloids. If a chemical compound occurs naturally with different ...

  6. Chemical substance - Wikipedia

    en.wikipedia.org/wiki/Chemical_substance

    While the term chemical substance is a precise technical term that is synonymous with chemical for chemists, the word chemical is used in general usage to refer to both (pure) chemical substances and mixtures (often called compounds), [14] and especially when produced or purified in a laboratory or an industrial process.

  7. Geochemistry of carbon - Wikipedia

    en.wikipedia.org/wiki/Geochemistry_of_carbon

    Yet it is the twelfth most common element there. In the rock of the lithosphere, carbon commonly occurs as carbonate minerals containing calcium or magnesium. It is also found as fossil fuels in coal and petroleum and gas. Native forms of carbon are much rarer, requiring pressure to form. Pure carbon exists as graphite or diamond. [1]

  8. Sedimentary rock - Wikipedia

    en.wikipedia.org/wiki/Sedimentary_rock

    Uluru (Ayers Rock) is a large sandstone formation in Northern Territory, Australia.. Sedimentary rocks can be subdivided into four groups based on the processes responsible for their formation: clastic sedimentary rocks, biochemical (biogenic) sedimentary rocks, chemical sedimentary rocks, and a fourth category for "other" sedimentary rocks formed by impacts, volcanism, and other minor processes.

  9. Eutectic system - Wikipedia

    en.wikipedia.org/wiki/Eutectic_system

    A phase diagram for a fictitious binary chemical mixture (with the two components denoted by A and B) used to depict the eutectic composition, temperature, and point. ( L denotes the liquid state.) A eutectic system or eutectic mixture ( / j uː ˈ t ɛ k t ɪ k / yoo- TEK -tik ) [ 1 ] is a type of a homogeneous mixture that has a melting point ...