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  2. Chemical coloring of metals - Wikipedia

    en.wikipedia.org/wiki/Chemical_coloring_of_metals

    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. [27] Brown for copper. Items are boiled in at least 3-day-old water solution of 12% copper sulfate, after color being developed, the material is washed, dried and waxed or varnished ...

  3. 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.

  4. 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 ...

  5. Color of chemicals - Wikipedia

    en.wikipedia.org/wiki/Color_of_chemicals

    The color of chemicals is a physical property of chemicals that in most cases comes from the excitation of electrons due to an absorption of energy performed by the chemical. The study of chemical structure by means of energy absorption and release is generally referred to as spectroscopy .

  6. Glass coloring and color marking - Wikipedia

    en.wikipedia.org/wiki/Glass_coloring_and_color...

    In borosilicate glasses rich in boron, sulfur imparts a blue color. With calcium it yields a deep yellow color. [4] Manganese can be added in small amounts to remove the green tint given by iron, or in higher concentrations to give glass an amethyst color. Manganese is one of the oldest glass additives, and purple manganese glass was used since ...

  7. Copper (color) - Wikipedia

    en.wikipedia.org/wiki/Copper_(color)

    At right is displayed the color copper penny. A US 2003 penny featuring Lincoln Copper penny is one of the colors in the special set of metallic Crayola crayons called Silver Swirls , the colors of which were formulated by Crayola in 1990.

  8. Flame test - Wikipedia

    en.wikipedia.org/wiki/Flame_test

    The flame test carried out on a copper halide. The characteristic bluish-green color of the flame is due to the copper. A flame test is relatively quick test for the presence of some elements in a sample. The technique is archaic and of questionable reliability, but once was a component of qualitative inorganic analysis.

  9. Thermochromism - Wikipedia

    en.wikipedia.org/wiki/Thermochromism

    Bis(diethylammonium) tetrachlorocuprate(II) ([(CH 3 CH 2) 2 NH 2] 2 CuCl 4) is a bright green solid material, which at 52–53 °C reversibly changes color to yellow. The color change is caused by relaxation of the hydrogen bonds and subsequent change of geometry of the copper-chlorine complex from planar to deformed tetrahedral, with ...