-
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
-
L: A laser and chemicals used to reach and alter inclusions in gemstones, usually diamonds.
-
B: Bleached using heat, light and/or other agents to lighten or remove color.
-
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.
-
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.
-
R: Irradiation using neutrons, gamma rays, beta particles or high energy electrons to alter color. May be followed by a heating process.
-
D: Dyed by the introduction of coloring matter to give a new color, intensify present color or improve color uniformity.
-
S: Stabilized using a colorless bonding agent (such as plastic); used on porous gemstones to add durability and improve appearance
-
(sometimes referred to as "I" impregnated).
-
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.
-
SYN: Synthetic materials with essentially the same optical, physical and chemical properties as a naturally occurring gemstone.
-
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.
-
U: Diffusion; chemicals used in conjunction with high temperatures to produce color and/or asterism-producing inclusions.
-
HP: Heating and pressure combined to effect desired alterations of color, clarity and/or phenomena.
-
W: Waxing/oiling; impregnation of colorless wax, paraffin and oil in porous, opaque or translucent gemstones to improve appearance.
-
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.