oxidizing - the process that forms oxides on the surface of metal. This is often done purposefully by applying heat or chemicals to a metal to achieve a desired darkening of metal.
[edit] Oxidizing and reducing agents
Substances that have the ability to oxidize other substances are said to be oxidative and are known as oxidizing agents, oxidants or oxidizers.
Oxidizing: Darkening the surface of metal by chemical or heat application.
Precious stones: Rare and costly gems, including diamonds, emeralds, rubies and sapphires.
Virtually any light-colored Sri Lankan sapphire can be heated to produce a yellow to golden color in an oxidizing atmosphere because these stones naturally possess the Mg2+ needed.
The colors are different in most cases when heated with an oxidizing and reducing flame, as well as when the bead is hot and cold. bed 1) Rock mass of one type surrounded by a different type of rock. 2) A deposit of granular rock caused from ...
Several involve the use of an acid with an oxidizing agent. A sodium dichromate pickle with a low percentage of sulfuric acid has been mentioned as a fire scale remover, though I have not used it for that.
Heat to a temperature between 1500 and 1700° centigrade in an oxidizing atmosphere tend to induce a moderate to deep yellow color in pale sapphires.
As the gem forms it is generally a blue-grey-green color, but when subjected to oxidizing conditions the iron in the crystals turns gold. Such conditions are common geologically, making the golden form much more prevalent than the blue.
To put it in simple terms, Sapphire heated in an oxidizing atmosphere lightens its color. Heating in a reducing atmosphere enhances the blue color.
secondary mineral in oxidizing zone of ore deposits containing lead and molybdenum
Association:
galena, cerussite, pyromorphite, smithsonite, calcite ...
The lacquer or varnish that protected antique brassware is usually worn away now. A slow oxidizing process takes place on the surface of brass, and if the oxide is very old, a caustic solution will be needed to remove it.
A processes that darkens the recesses of jewelry to give an antique appearance. Sterling silver is antiqued with an oxidizing agent and costume jewelry is often antiqued with a thinned paint.
Repeat treatment to patchy stones at about 900oC, in oxidizing environment to get colorless, yellow, orange or red. Unaffected stones can be recycled until yielding proper color. Treatment usually yields colorfast stones, but not always.
Anvil vs. Block for Making Jewelry
Hammers for Metal Jewelry Making
It's Black or White - Oxidizing
About Metal Casting Services
Making Charms Using Lost Wax Casting ...
Bloodstone: A variety of chalcedony that is dark green red spots resembling blood. These red spots are iron oxide. Actually oxidizing of the green. Found in Australia, Brazil, China, India, USA.
Sterling silver is 92.5% silver and 7.5% copper. The copper in the alloy reacts to the sulphur
compounds in the air (Sulphur Dioxide is a major component of air pollution) by tarnishing (oxidizing).
Indonesian cast components are also finished by hand-a process that includes forming and soldering jump rings, oxidizing, cleaning, and polishing. The master mold for the casting of components is also carved by hand. No two pieces are exactly alike.
Fall 1971, Burning (oxidizing) rough diamond crystal to improve surface color, p. 345, 1p.
Winter 1971, Diamond and zircon (or strontium titanite, spinel, etc.) doublets, p. 375, 2pp.
Winter 1971, Diamonds treated pink, p. 380, 1p.
 See also: Color, Metal, Crystal, Natural, Rough
  
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