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  2. Feldspar - Wikipedia

    en.wikipedia.org/wiki/Feldspar

    Feldspars make up about 60% of the Earth's crust [3] and 41% of the Earth's continental crust by weight. [5] [6] Feldspars crystallize from magma as both intrusive and extrusive igneous rocks [7] and are also present in many types of metamorphic rock. [8] Rock formed almost entirely of calcic plagioclase feldspar is known as anorthosite. [9]

  3. Orthoclase - Wikipedia

    en.wikipedia.org/wiki/Orthoclase

    Together with the other potassium feldspars, orthoclase is a common raw material for the manufacture of some glasses and some ceramics such as porcelain, and as a constituent of scouring powder. Some intergrowths of orthoclase and albite have an attractive pale luster and are called moonstone when used in jewelry. Most moonstones are ...

  4. Plagioclase - Wikipedia

    en.wikipedia.org/wiki/Plagioclase

    Plagioclase displaying cleavage. (unknown scale) In volcanic rocks, fine-grained plagioclase can display a "microlitic" texture of many small crystals. Plagioclase (/ ˈ p l æ dʒ (i) ə ˌ k l eɪ s, ˈ p l eɪ dʒ-,-ˌ k l eɪ z / PLAJ-(ee)-ə-klayss, PLAYJ-, -⁠klayz) [4] is a series of tectosilicate (framework silicate) minerals within the feldspar group.

  5. Moonstone (gemstone) - Wikipedia

    en.wikipedia.org/wiki/Moonstone_(gemstone)

    Moonstone is a sodium potassium aluminium silicate ((Na,K)AlSi 3 O 8) of the feldspar group that displays a pearly and opalescent schiller. [1] [2] An alternative name for moonstone is hecatolite [2] (from goddess Hecate).

  6. Anorthite - Wikipedia

    en.wikipedia.org/wiki/Anorthite

    Anorthite (an = not, ortho = straight) is the calcium endmember of the plagioclase feldspar mineral series. The chemical formula of pure anorthite is CaAl 2 Si 2 O 8. Anorthite is found in mafic igneous rocks. Anorthite is rare on the Earth [6] but abundant on the Moon. [7]

  7. Potassium feldspar - Wikipedia

    en.wikipedia.org/wiki/Potassium_feldspar

    Potassium feldspar refers to a number of minerals in the feldspar group that contain large amounts of potassium in the crystal lattice. Orthoclase (endmember formula K Al Si 3 O 8), an important tectosilicate mineral that forms igneous rock; Microcline, chemically the same as orthoclase, but with a different crystalline structure

  8. Microcline - Wikipedia

    en.wikipedia.org/wiki/Microcline

    Feldspar (amazonite) Perthite is either microcline or orthoclase with thin lamellae of exsolved albite. Amazon stone, or amazonite, is a green variety of microcline. It is not found anywhere in the Amazon Basin, however. The Spanish explorers who named it apparently confused it with another green mineral from that region.

  9. Quartz-porphyry - Wikipedia

    en.wikipedia.org/wiki/Quartz-porphyry

    Phenocrysts of clear glassy rounded quartz and white orthoclase feldspar are set in a fine-grained matrix. Sample is just over 10 cm long Sample is just over 10 cm long Quartz-porphyry , in layman's terms, is a type of volcanic ( igneous ) rock containing large porphyritic crystals of quartz .