materials science

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  Botryoidal

  Common examples include: chalcedony, pyrite, smithsonite, hemimorphite A botryoidal (/ˌbɒtriˈɔɪdəl/ BOT-ree-OY-dəl) texture or mineral habit, is one in which the mineral has an external form composed of many rounded segments, named for the Ancient Greek βότρυς (bótrus), meaning “a bunch of grapes“. This is a common form for many minerals, particularly hematite and malachite, which are known for frequently forming botryoidal masses. It is also a common form of goethite, smithsonite, fluorite, and chrysocolla.…

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  Tetrahedral

  Common examples include: tetrahedrite, spinel, sphalerite, magnetite

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  Scalenohedral

  Common examples include: calcite, rhodochrosite, titanite In crystallography, “regular” right “symmetric” “didigonal” (8-faced) and ditrigonal (12-faced) scalenohedra exist. The smallest geometric scalenohedra have eight faces, and are topologically identical to the regular octahedron. In this case (2n = 2×2), in crystallography, a “regular” right “symmetric” “didigonal” (8-faced) scalenohedron is called a tetragonal scalenohedron.

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  Rhombohedral

  Common examples include: calcite, rhodochrosite, siderite

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  Pseudo-Hexagonal

  Common examples include: aragonite, chrysoberyl

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  Prismatic

  Common examples include: beryl, tourmaline, vanadinite, emerald

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  Octahedral

  Common examples include: diamond, fluorine, fluorite, magnetite, pyrite

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  Icositetrahedral

  Common examples include: spessartine

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  Hexagonal

  Common examples include: emerald, galena, quartz, hanksite, vanadinite

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  Equant/Stout

  Common examples include: apophyllite, olivine, garnet