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  2. 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 ...

  3. Pyrotechnic colorant - Wikipedia

    en.wikipedia.org/wiki/Pyrotechnic_colorant

    The red lithium flame leads to lithium's use in flares and pyrotechnics Copper compounds glow green or blue-green in a flame. Calcium compounds glow orange in a flame. Sodium compounds glow yellow in a flame. A pyrotechnic colorant is a chemical compound which causes a flame to burn with a particular color.

  4. Patina - Wikipedia

    en.wikipedia.org/wiki/Patina

    Patina (/ p ə ˈ t iː n ə / pə-TEE-nə or / ˈ p æ t ɪ n ə / PAT-ih-nə) is a thin layer that variously forms on the surface of copper, brass, bronze, and similar metals and metal alloys (tarnish produced by oxidation or other chemical processes), or certain stones [1] and wooden furniture (sheen produced by age, wear, and polishing), or ...

  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. Colored fire - Wikipedia

    en.wikipedia.org/wiki/Colored_fire

    Generally, the color of a flame may be red, orange, blue, yellow, or white, and is dominated by blackbody radiation from soot and steam. When additional chemicals are added to the fuel burning, their atomic emission spectra can affect the frequencies of visible light radiation emitted - in other words, the flame appears in a different color ...

  7. 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.

  8. Potassium dichromate - Wikipedia

    en.wikipedia.org/wiki/Potassium_dichromate

    Pure silver will turn the solution bright red, sterling silver will turn it dark red, low grade coin silver (0.800 fine) will turn brown (largely due to the presence of copper which turns the solution brown) and even green for 0.500 silver. Brass turns dark brown, copper turns brown, lead and tin both turn yellow while gold and palladium do not ...

  9. Ceramic colorants - Wikipedia

    en.wikipedia.org/wiki/Ceramic_colorants

    Copper's carbonate form (CuCO 3) is commonly used to produce greens, turquoise, and copper reds. If need be, copper oxide (CuO) can be substituted but has a larger particle size and glazes should be adjusted to generally half the amount called for. In barium based glazes greenish blues often result from copper.