Colored Stones 6 - Key Terms (PDF)

Colored Stones 6 Key Terms Bleaching—A treatment that uses chemicals to lighten or Oxidizing environment—An oxygen-rich environment that remove color. surrounds a gem during heat treatment, causing certain...

Colored Stones 6 Key Terms Bleaching—A treatment that uses chemicals to lighten or Oxidizing environment—An oxygen-rich environment that remove color. surrounds a gem during heat treatment, causing certain color-causing trace elements to lose electrons. Clarity enhancement—Treatment that improves the apparent clarity of a gem with a colorless or near- Polymer—A liquid filling material that’s very durable when colorless filler. it dries. Colorless impregnation—Filling of pores or other openings with melted wax, resin, polymer, or plastic to Quench crackling—A rapid heating and cooling process improve appearance and stability. that produces fractures in a stone so it will accept dye. Dyeing—A treatment that adds color or affects color by Reducing environment—An oxygen-poor environment deepening it, making it more even, or changing it. that surrounds a gem during heat treatment, causing certain color-causing trace elements to gain electrons. Flux—A compound that can dissolve another compound at a lower temperature than its own melting point. Resin—A clear, viscous substance that’s used to fill Flux healing—Heat treatment in the presence of a flux fractures in gemstones. that results in the sealing of a fracture or cavity. Smoke treatment—Heating a wrapped opal until smoke Fracture (fissure) filling—Use of a colorless to near- or ash penetrates its surface to darken it and bring out its colorless filler to conceal fractures and improve the play-of-color. apparent clarity of a gem. Geuda—Milky, grayish, or brownish corundum that can be Sugar treatment—Soaking an opal in a hot sugar solution treated to a fine blue color. and then in sulfuric acid to darken it and bring out its play-of-color. Hardener—A chemical that treaters mix with some resins to cause them to solidify. Surface modification—Altering a gem’s appearance by applying backings, coatings, or coloring agents like Heat treatment—Exposing a gem to rising temperatures paint. for the purpose of changing its appearance. Lattice diffusion—A treatment in which a gem is exposed Treatment—Any human-controlled process, beyond to high temperatures and chemicals to allow penetration cutting and polishing, that improves the appearance, of color-causing elements. durability, or value of a gem. 302