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Treatments
Treatments
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The history of treating gemstones with a variety of methods to improve their appearance goes back thousands of years. Today, gemstones are commonly treated to improve their color, clarity and/or durability. These treatments are various, common and acceptable in the industry as long as disclosure of the treatment is made to the buyer. It is estimated as many as 99% of rubies, sapphires and emeralds are treated, and verified un-treated examples in finer qualities command a premium price over the treated varieties. Order Now

Many popular gem types are treated, and all permanent techniques are universally accepted, again, as long as disclosure of the treatment is made to the buyer. Please note that the term "natural gemstones" refers to those formed in the earth, whether or not they have been treated after mining. These are distinctly different from "lab created", "man made" or "synthetic" gems which must be clearly labeled as "man made materials" and not "natural gemstones" according to Federal Trade Commission (FTC) law. Gemstones which are a combination of natural and man made materials must be declared as "assembled stones". Click Here to see a list of Various Other Treatments. Order Now

Gemstone types Treatments and benefits Care instructions
Agate (see Chalcedony) Routinely heated, bleached or dyed to improve color Normal care
Alexandrite Not routinely enhanced Normal care
Almandite (Garnet) Not routinely enhanced Normal care but avoid sudden temperature changes
Amazonite Impregnated with wax, oil, plastic or colorless hardened resins to stabilize and improve appearance Avoid heat, household chemicals and ultrasonic
Amber Routinely heated or dyed to deepen or add color Avoid chemicals, steam and ultrasonic cleaning
Amethyst (Quartz) Routinely heated and/or irradiated to improve color Normal care
Ammonite (Ammolite) Impregnated with colorless hardened resins to stabilize and improve appearance Avoid heat, household chemicals and ultrasonic
Ametrine (Quartz) Routinely heat- treated to improve color Normal care
Andalusite Occasionally heat-treated to improve color Normal care
Apatite Occasionally heated to improve color Avoid chemicals, steam and ultrasonic cleaning
Aquamarine (Beryl) Routinely heated to improve color Normal care
Aventurine (Quartz) Occasionally dyed to improve color Normal care
Azurite Occasionally filled with epoxy or resin to stabilize and improve surface appearance Avoid chemicals, steam and ultrasonic cleaning
Azure-malachite Rarely filled with epoxy or resin for smoother surface and improve durability Avoid chemicals, steam and ultrasonic cleaning
Bixbite (red beryl) Routinely oiled or resin treated to improve clarity Avoid heat, household chemicals and ultrasonic
Topaz Usually irradiated and heated to produce color Normal care but avoid sudden temperature changes
Canary Aqua ™ Routinely irradiated to enhance color Normal care but avoid excessive heat.
Cat's Eye Chrysoberyl Rarely irradiated to darken color Normal care
Chalcedony Routinely heat-treated, bleached and dyed to induce different colors Normal care
Chrome Diopside Not routinely enhanced Avoid chemicals and sudden temperature changes
Chrysoberyl transparent varieties (yellow, green, brown) Not routinely enhanced Normal care
Chrysoprase Not routinely enhanced Normal care
Citrine (Quartz) Routinely heat-treated to improve color Normal care
Coral Routinely dyed, bleached and/or impregnated with wax, plastic or resin to improve color and stability Avoid chemicals, steam and ultrasonic cleaning
Demantoid (Garnet) Not routinely enhanced Normal care but avoid sudden temperature changes
Diamond - colorless Occasionally laser drilled and then filled with lead glass to improve clarity. Occasionally fracture filled with lead glass to improve clarity. Occasionally HTHP treated to improve color Normal care
Diamond - colored Often irradiated to improve color Normal care
Emerald (Beryl) Routinely oiled or resin treated to improve clarity Avoid chemicals, steam and ultrasonic cleaning
Fluorite Routinely heated and/or irradiated to improve color Avoid chemicals, steam and ultrasonic cleaning
Garnet (also listed by type) Not routinely enhanced Normal care but avoid sudden temperature changes
Gaspeite Occasionally stabilized with plastic Normal care
Goshenite Not routinely enhanced Normal care
Heliodor Irradiated to improve color Normal care
Hematite Not routinely enhanced Normal care
Hessonite (Garnet) Not routinely enhanced Normal care but avoid sudden temperature changes
Howlite Routinely dyed to improve color and to emulate turquoise Avoid steam and ultrasonic cleaning
Indicolite (Tourmaline) Routinely heat-treated to improve color Normal care but avoid sudden temperature changes
Iolite Not routinely enhanced Normal care but avoid sudden temperature changes
Jadeite Type “A” Not routinely enhanced in higher qualities. Lower grades routinely filled with wax to reduce visibility of cracks and improve surface appearance Type “B” Routinely bleached and dyed. Routinely filled with wax to reduce visibility of cracks Normal care
Jasper Occasionally dyed to enhance color Normal care
Jet Not routinely enhanced Avoid steam and ultrasonic cleaning
Kornerupine Not routinely enhanced Normal care but avoid rough handling
Kunzite (Spodumene) Occasionally heated and/or irradiated to enhance color Avoid sudden temperature changes, rough handling and exposure to strong light.
Kyanite Not routinely enhanced Avoid rough handling, steam and ultrasonic cleaning
Labradorite Not routinely enhanced Avoid rough handling, steam and ultrasonic cleaning
Lapis Lazulli Routinely dyed, wax or resin impregnated to improve color and luster Avoid chemicals, steam and ultrasonic cleaning
Lepidolite Not routinely enhanced Normal care
Malachite Occasionally dyed, wax or resin impregnated to improve color uniformity and surface appearance Avoid chemicals, steam and ultrasonic cleaning
Mariposite Not routinely enhanced Normal care
Moldavite Not routinely enhanced Normal care
Moonstone Not routinely enhanced Normal care
Morganite (Beryl) Routinely heated and/or irradiated to enhance color Normal care
Mother of Pearl Routinely dyed to produce a wide variety of colors Avoid chemicals, steam and ultrasonic cleaning
Muscovite Not routinely enhanced Normal care
Onyx (Chalcedony) Black Onyx Routinely heat-treated, irradiated, bleached and dyed to induce different colors Always dyed Normal care
Opal Occasionally oil, wax or resin treated to hide cracks and provide stability. “Matrix” variety commonly treated with sugar and acid depositing carbon in pore spaces significantly darkening the stone Avoid chemicals, steam and ultrasonic cleaning
Pearl Routinely bleached, dyed and/or irradiated to improve or induce color Avoid chemicals (including hairspray and cosmetics), steam and ultrasonic cleaning
Peridot Not routinely enhanced Avoid chemicals, steam and ultrasonic cleaning, sudden temperature changes
Petalite Not routinely enhanced Avoid rough handling, ultrasonic cleaning
Petrified Wood (see Chalcedony) Occasionally bleached and heated to improve color Normal care
Pietersite Not routinely enhanced Normal care
Pyrope (Garnet) Not routinely enhanced Normal care but avoid sudden temperature changes
Rainbow Calsilica An artificial material created for carving/lapidary purposes. Avoid chemicals, steam and ultrasonic cleaning
Rhodochrosite Not routinely enhanced Avoid chemicals, rough handling, and excessive heat.
Rhodolite (Garnet) Not routinely enhanced Normal care but avoid sudden temperature changes
Rhodonite Occasionally dyed to even color Normal care
Rosenite™ (Garnet) Not routinely enhanced Normal care but avoid sudden temperature changes
Rubellite (Tourmaline) Routinely heated and/or irradiated to improve color Normal care but avoid sudden temperature changes
Ruby Routinely heated to improve color and/or clarity. Occasionally diffusion heat treated with chemicals to improve color. Often clarity enhanced with borax and/or lead glass to fill fissures and fractures. Occasionally enhanced by a combination of these treatments. Normal care
Rutilated Quartz Not routinely enhanced Normal care
Sapphire Routinely heated to improve color and/or clarity. Occasionally diffusion heat treated with chemicals to improve color. Occasionally clarity enhanced with borax and/or lead glass to fill fissures and fractures, and occasionally enhanced by a combination of these treatments. Normal care
Scapolite Routinely irradiated for color enhancement Avoid steam and ultrasonic cleaning, avoid exposure to strong light
Serpentine Routinely dyed and/or impregnated with waxe to improve appearance and enhance colors Avoid steam and ultrasonic cleaning
Shell Commonly dyed to produce a wide variety of colors Avoid chemicals, steam and ultrasonic cleaning
Smokey Quartz Routinely heat-treated or irradiated to improve color Normal care
Sodalite Not routinely enhanced Avoid chemicals, steam and ultrasonic cleaning
Spessartite (Garnet) Not routinely enhanced Normal care but avoid sudden temperature changes
Sphene Not routinely enhanced Avoid chemicals, sudden temperature changes, and rough handling
Spinel Not routinely enhanced Normal care
Sugilite Not routinely enhanced Avoid steam and ultrasonic cleaning
Sunstone Not routinely enhanced Avoid chemicals, steam and ultrasonic cleaning
Tanzanite Routinely heated to remove brown tones and purify , violet- or violet colors Avoid steam, ultrasonic cleaning and sudden temperature changes
Tiger Iron Not routinely enhanced Normal care
Tiger's Eye (Quartz) Routinely heat-treated, dyed or bleached to enhance color Avoid sudden temperatures changes and strong chemicals
Topaz (other than ) Routinely heated to enhance colors Normal care but avoid sudden temperature changes
Tourmaline Greens and s routinely heat-treated to enhance color. Normal care but avoid sudden temperature changes
Tsavorite (Garnet) Not routinely enhanced Normal care but avoid sudden temperature changes
Turquoise Routinely stabilized (impregnated) with plastic or resins to enhance durability and color, and occasionally dyed Avoid chemicals, steam and ultrasonic cleaning. Perspiration and cosmetics may alter color.
Unakite Not routinely enhanced Avoid chemicals, steam and ultrasonic cleaning
Variscite Occasionally stabilized (impregnated) with plastic or resins to enhance durability and color, and occasionally dyed Avoid chemicals, steam and ultrasonic cleaning
Verdelite (Tourmaline) Routinely heated to improve color Normal care but avoid sudden temperature changes
White Aqua™ (Beryl) Routinely heated to remove faint color Normal care
Yellow Beryl (Heliodor) Routinely heated and/or irradiated to improve color Normal care but avoid excessive heat
Zircon Routinely heat-treated to induce color and improve yellows and reds Avoid abrasives, rough wear and exposure to strong light.

Various Other Treatments:

  • Bleaching: Use of chemicals to lighten or remove a gem's color.
  • Coating: Use of surface treatments such as films, lacquers, etc. to provide color or other special effects.
  • Dyeing: The introduction of coloring matter into a gem to give it a new color or greater intensity.
  • Filling: Introduction of colorless borax, lead glass or other substances into cracks through heating.
  • Gamma/Electron Radiation: The use of gamma or electron irradiation for the purpose of changing a gem's color, may be followed by a heating process to stabilize the color. Such stones do not exhibit residual radioactivity.
  • Heating: The use of heat to clarify, change color or create phenomena in gems.
  • Infilling: The intentional filling of surface breaking cracks and cavities with a foreign material such as synthetic resins with hardeners (Opticon), glass or plastic.
  • Lasering: The use of a laser to drill into a stone and remove or alter an inclusion, refers most often to diamonds.
  • Oiling or Resin Infusion: The intentional filling of surface breaking cavities and cracks in transparent or translucent gems with a colorless oil, wax, resin or man-made unhardened resin.
  • Irradiation: The use of neutron bombardment to alter color. This process creates residual radioactivity and such stones must receive a Nuclear Regulatory Commission safety release prior to sale. Usually used in combination with other radiation and or heating treatments.
  • Bonding: The intentional use of a colorless bonding agent (usually plastic) within a porous gemstone.
  • Diffusion: The use of specific chemicals during a high temperature heating process for the purpose of penetrating the surface layer (usually to a slight depth only) with coloring or star-making chemicals.
  • Waxing/Oiling: The impregnation of colorless wax, oil or paraffin into porous opaque gems to improve appearance.

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