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  2. Streak (mineralogy) - Wikipedia

    en.wikipedia.org/wiki/Streak_(mineralogy)

    Streak plates with pyrite (left) and rhodochrosite (right). The streak of a mineral is the color of the powder produced when it is dragged across an unweathered surface. Unlike the apparent color of a mineral, which for most minerals can vary considerably, the trail of finely ground powder generally has a more consistent characteristic color, and is thus an important diagnostic tool in mineral ...

  3. Mica - Wikipedia

    en.wikipedia.org/wiki/Mica

    Micas (/ ˈ m aɪ k ə z / MY-kəz) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into fragile elastic plates. This characteristic is described as perfect basal cleavage. Mica is common in igneous and metamorphic rock and is occasionally found as small flakes in ...

  4. Rock (geology) - Wikipedia

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

    The proportion of silica in rocks and minerals is a major factor in determining their names and properties. [7] Rock outcrop along a mountain creek near Orosí, Costa Rica. Rocks are classified according to characteristics such as mineral and chemical composition, permeability, texture of the constituent particles, and particle size.

  5. Mineral - Wikipedia

    en.wikipedia.org/wiki/Mineral

    The streak of a mineral refers to the colour of a mineral in powdered form, which may or may not be identical to its body colour. [79] The most common way of testing this property is done with a streak plate, which is made out of porcelain and coloured either white or black.

  6. List of minerals - Wikipedia

    en.wikipedia.org/wiki/List_of_minerals

    This is a list of minerals which have Wikipedia articles.. Minerals are distinguished by various chemical and physical properties. Differences in chemical composition and crystal structure distinguish the various species.

  7. Corundum - Wikipedia

    en.wikipedia.org/wiki/Corundum

    Corundum is a crystalline form of aluminium oxide (Al 2 O 3) typically containing traces of iron, titanium, vanadium, and chromium. [3] [4] It is a rock-forming mineral.It is a naturally transparent material, but can have different colors depending on the presence of transition metal impurities in its crystalline structure. [7]

  8. 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

  9. Serpentine subgroup - Wikipedia

    en.wikipedia.org/wiki/Serpentine_subgroup

    Serpentine subgroup is a set of common rock-forming hydrous magnesium iron phyllosilicate ((Mg,Fe) 3 Si 2 O 5 4) minerals, resulting from the metamorphism of the minerals that are contained in mafic to ultramafic rocks. [6] They may contain minor amounts of other elements including chromium, manganese, cobalt or nickel.