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  2. Soil color - Wikipedia

    en.wikipedia.org/wiki/Soil_color

    Highly oxidized red soil in Tirunelveli District, India. Red colors often indicate iron accumulation or oxidation in oxygen-rich, well-aerated soils. [4] Iron concentrations caused by redox reactions because of diffusion of iron in crystalline and metermorphic rock, in periodically saturated soils may also present red colors, particularly along root channels or pores.

  3. Malachite - Wikipedia

    en.wikipedia.org/wiki/Malachite

    Malachite is a copper carbonate hydroxide mineral, with the formula Cu 2 CO 3 (OH) 2.This opaque, green-banded mineral crystallizes in the monoclinic crystal system, and most often forms botryoidal, fibrous, or stalagmitic masses, in fractures and deep, underground spaces, where the water table and hydrothermal fluids provide the means for chemical precipitation.

  4. Patina - Wikipedia

    en.wikipedia.org/wiki/Patina

    The Statue of Liberty gets its famous green color from the natural patina formed on its copper surface. The green patina that forms naturally on copper and bronze, sometimes called verdigris, usually consists of varying mixtures of copper chlorides, sulfides, sulfates, and carbonates, depending upon environmental conditions such as sulfur ...

  5. Verdigris - Wikipedia

    en.wikipedia.org/wiki/Verdigris

    The Statue of Liberty, showing advanced patination; verdigris is responsible for the statue's iconic green colour.. Verdigris (/ ˈ v ɜːr d ɪ ɡ r iː (s)/) [1] is a common name for any of a variety of somewhat toxic [2] [3] [4] copper salts of acetic acid, which range in colour from green to a bluish-green depending on their chemical composition.

  6. Copper - Wikipedia

    en.wikipedia.org/wiki/Copper

    Unoxidized copper wire (left) and oxidized copper wire (right) The East Tower of the Royal Observatory, Edinburgh, showing the contrast between the refurbished copper installed in 2010 and the green color of the original 1894 copper. Copper does not react with water, but it does slowly react with atmospheric oxygen to form a layer of brown ...

  7. Green pigments - Wikipedia

    en.wikipedia.org/wiki/Green_pigments

    Emerald Green, also known as Paris Green, Scheele's Green, Schweinfurt green and Vienna Green, is a synthetic inorganic compound, made by a reaction of sodium arsenite with copper(II) acetate. While it makes a beautiful rich green, the color of the emerald stone, it is highly toxic , due to a main ingredient, arsenic . [ 18 ]

  8. Azurite - Wikipedia

    en.wikipedia.org/wiki/Azurite

    Color code: red = O, green = Cu, gray = C, white = H) Azurite has the formula Cu 3 (CO 3) 2 (OH) 2, with the copper(II) cations linked to two different anions, carbonate and hydroxide. It is one of two relatively common basic copper(II) carbonate minerals, the other being bright green malachite. Aurichalcite is a rare basic carbonate of copper ...

  9. Chemical coloring of metals - Wikipedia

    en.wikipedia.org/wiki/Chemical_coloring_of_metals

    Brown or black can be used as a base color for copper patina. If the amount of chlorides decreases the color will be more bluish-green, if carbonate decreases, more yellow-green. [27] Black for copper. Solution of sodium polysulfide 2.5%, items must be submerged in the solution after color developing, wash, dry and wax or varnish colored object ...