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ASBL: Assembled from multiple layers or combinations of manufactured and/or natural material fused, bonded or otherwise joined together to increase stability and/or imitate the appearance of a natural gemstone, create a unique design or generate unusual color combinations. Example: Opal triplets
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L: A laser and chemicals used to reach and alter inclusions in gemstones, usually diamonds.
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B: Bleached using heat, light and/or other agents to lighten or remove color.
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O: Oiling/resin infusion; the filling of surface breaking fissures with colorless oil, wax, resin or other colorless substances, except glass or plastic, to improve the gemstone's appearance.
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C: Coating on the surface with such enhancements as lacquering, enameling, inking, foiling or sputtering of films to improve appearance, provide color or add other special effects.
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R: Irradiation using neutrons, gamma rays, beta particles or high energy electrons to alter color. May be followed by a heating process.
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D: Dyed by the introduction of coloring matter to give a new color, intensify present color or improve color uniformity.
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S: Stabilized using a colorless bonding agent (such as plastic); used on porous gemstones to add durability and improve appearance
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(sometimes referred to as "I" impregnated).
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F: Filling of surface-breaking cavities or fissures with colorless glass, plastic, solidified borax or similar substances (visible under 10X magnification); improves durability, appearance and/or adds weight.
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SYN: Synthetic materials with essentially the same optical, physical and chemical properties as a naturally occurring gemstone.
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H: Heated to effect desired alterations of color, clarity and/or phenomena. If residue of foreign substances in open fissures is visible under properly illuminated 10X magnification, "HF" should be used.
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U: Diffusion; chemicals used in conjunction with high temperatures to produce color and/or asterism-producing inclusions.
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HP: Heating and pressure combined to effect desired alterations of color, clarity and/or phenomena.
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W: Waxing/oiling; impregnation of colorless wax, paraffin and oil in porous, opaque or translucent gemstones to improve appearance.
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IMIT: Imitation product fabricated in such materials as glass, ceramic or plastic designed to imitate or resemble the appearance, but not duplicate the characteristic properties of a natural gemstone.
