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  2. Chert - Wikipedia

    en.wikipedia.org/wiki/Chert

    Chert (/ tʃ ɜːr t /) is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, [1] the mineral form of silicon dioxide (SiO 2). [2] Chert is characteristically of biological origin, but may also occur inorganically as a chemical precipitate or a diagenetic replacement, as in petrified wood. [3]

  3. Concretion - Wikipedia

    en.wikipedia.org/wiki/Concretion

    For example, concretions in sandstones or shales are commonly formed of a carbonate mineral such as calcite; those in limestones are commonly an amorphous or microcrystalline form of silica such as chert, flint, or jasper; while those in black shale may be composed of pyrite. [18]

  4. Jasper - Wikipedia

    en.wikipedia.org/wiki/Jasper

    Jasper, an aggregate of microgranular quartz and/or cryptocrystalline chalcedony and other mineral phases, [1] [2] is an opaque, [3] impure variety of silica, usually red, yellow, brown or green in color; and rarely blue.

  5. Talk:Jasper - Wikipedia

    en.wikipedia.org/wiki/Talk:Jasper

    Jasper is a form of iron-rich chert and as such it is microgranular, composed of microscopic silica sediments. It is opaque, only translucent in very thin sections, and is, in fact, a rock. There are numerous texts that detail the differences between quartz, chalcedony, chert, and jasper, none of which seem to be sited here.

  6. List of rock types - Wikipedia

    en.wikipedia.org/wiki/List_of_rock_types

    Novaculite – Type of rock – A type of chert found in Oklahoma, Arkansas, and Texas Pietersite – Commercial term for a variety of chalcedony Pyrolite – theoretical rock making up the earth's upper mantle Pages displaying wikidata descriptions as a fallback – A chemical analogue considered to theoretically represent the Earth's upper mantle

  7. Chalcedony - Wikipedia

    en.wikipedia.org/wiki/Chalcedony

    Opaque varieties are sometimes referred to as jasper. [4] Fire agate shows iridescent phenomena on a brown background; iris agate shows exceptional iridescence when light (especially pinpointed light) is shone through the stone. Landscape agate is chalcedony with a number of different mineral impurities making the stone resemble landscapes. [9]

  8. Puddingstone (rock) - Wikipedia

    en.wikipedia.org/wiki/Puddingstone_(rock)

    The jasper conglomerate consists of subrounded pebbles of red jasper, black chert, white quartzite, hematite, and semi-transparent quartz in a matrix of coarsely grained quartzite. It contains circa 30% to 90% of pebbles.

  9. Jaspillite - Wikipedia

    en.wikipedia.org/wiki/Jaspillite

    Jaspillite (or jaspilite), also called itabirite or jasper taconite, is a chemical rock formed similar to chert, but is generally quite iron-rich. Jaspillite is typically a banded mixture of hematite and quartz common in the banded iron formation rocks of Proterozoic and Archaean age in the Canadian Shield .