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- Gemstone Enhancement Definitions
Gemstone Enhancement Definitions and Gemstone Terms
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| Gemstone Enhancement Definitions with On-Air Codes | ||
| assembled | The assembling of natural with natural and/or man-made parts to improve durability or appearance. Examples: opal doublet, mabe pearl. | AS |
| autoclave treated | A method of applying heat with pressure. Commonly done with copal to create green amber. This treatment simulates a rapid aging process, making the stability of copal comparable to amber while also creating a green color. | |
| bleached | The use of heat, light, and/or chemicals or other agents to lighten or remove a gemstone's color. This is sometimes accompanied by subsequent dying and/or impregnating to stabilize the resulting color. Examples: cultured pearl, golden coral, B-jade | BL |
| coated | The use of such surface enhancements as lacquering, enameling, inking, foiling, or sputtering of films to improve appearance, improve durability,provide color or add other special effects. Examples: some pearls, black star sapphires, some topaz, many beads. | CTD |
| CVD coated | "Chemical Vapor Deposition" - A high-tech coating that is commonly applied to the pavillion (bottom) of stones to change or improve their color. Examples: diamond, mystic topaz. | CVD |
| channel/pipe diffusion* | The high temperature diffusion of coloring elements, such as copper, along certain channels in feldspars. Example: andesine-labradorite. *Research still in progress | DIF |
| dyed/stained | The introduction of coloring matter into a gemstone to give it new color, intensify existing color or improve color uniformity. Examples: dyed green jadeite, lapis. | DYED |
| fracture filled | The filling of surface-breaking cavities or fissures with colorless glass, plastic, resin or some similar substance. This process may improve appearance, durability and/or weight. Examples: ruby, emerald. | FF |
| lead glass filling | A similar process to "fracture filled" using lead glass. Performed at lower temperatures, this is a less durable treatment and should be treated gently. Requires Special Care.Examples: plum star ruby, some ruby, some sapphire. | LGF |
| flux healed | During heat enhancement, fluxes (or heat alone) may be used to heal fractures/fissures which were formerly open. The process dissolves the walls of the fractures and redeposits the molten gem material, healing the fractures closed. Example: ruby. | FH |
| heated | The use of heat to alter color, clarity, and/or phenomena. Examples: ruby, sapphire, tanzanite, aquamarine, demantoid garnet. | HE |
| HPHT | The use of high heat and pressure combined to affect desired alterations of color and/or clarity. Example: colored and near-colorless diamonds. | HPHT |
| impregnated | The impregnation of a porous gemstone with a colorless agent (usually plastic) to give it greater durability and improve appearance. Examples: stabilized turquoise, coral. | IMP |
| irradiated | The use of neutron, gamma, ultraviolet and/or electron bombardment to alter a gemstone's color. The irradiation may be followed by a heating/annealing process. Examples: blue topaz, colored diamonds. | IRR |
| lasered | The use of a laser and chemicals to reach and alter inclusions. Example: diamond. | LAS |
| surface diffusion | The outside-in diffusion of elements via high-temperature heat treatment to produce a layer of color and/or asterism. Examples: some blue sapphire, some star sapphire. | DIF |
| lattice diffusion | The heat treatment at high temperatures with elements that deeply penetrate the gem material to alter the color. Examples: padparadscha sapphire, yellow sapphire. | BE DIF |
| oiled/resin infused | The filling of surface-breaking fissures with a colorless oil, wax, resin, or other colorless substance except glass or plastic, to improve the gemstone's appearance. Example: emerald and any stone with surface reaching fissures. | INF |
| pressed | The process of partially melting and pressing together smaller pieces or powders of natural resins such as amber and copal. Pressed amber retains the same properties of unpressed amber. In addition, it usually improves clarity and may have color added. | PRS |
| Quench-Crackled | A process mainly applied to quartz. By placing super-cooled stones into a very hot fluid, can add color while inducing a pattern of cracks | QCR |
| PVD coated | Physical Vapor Deposition Coated - A coating that is commonly applied to the surface of the product; which is then sealed with a polymer to protect it. Examples: Watches. | PVD |
| reconstructed | Small particles of natural material compressed and bonded into a larger whole. | RECON |
| smoke | In the smoke treatment process, the opals are wrapped in silver foil paper and heated. The smoke penetrates the opal and darkens the background color. This process results in a brighter play of color since the background is darkened | SM |
| stabilized | Not to be confused with reconstituted turquoise, the more valuable stabilized turquoise is solid, whole turquoise that has been filled with colorless wax or resin to fill tiny gaps within it, providing a polished finish that protects the stone against breakage and discoloration resulting from exposure to skin oils, etc. Stabilization does not add color, but the color may improve as a byproduct of thetreatment. Stabilization only serves to protect the turquoise and help it retain its original, natural color. | STB |
| sugar acid | In the sugar treatment process, the matrix opals are heated in a saturated sugar solution. The matrix material absorbs this sugar. It is then immersed in concentrated sulfuric acid. A chemical reaction takes place between the sugar and acid, leaving only the remaining carbon. This carbon darkens the background color of the gems. As a result the play-of-color in the stone appears brighter. | SA |
| waxed/oiled | The impregnation of a colorless wax, paraffin, and/or oil in porous gemstones to improve their appearance. Example: coral, amazonite. | W=WAXED O=OIL |
| Zachary process | Enhanced turquoise has been treated with chemicals, and then heated. The heating process eliminates any residual chemicals in the turquoise. Unlike natural turquoise, enhanced turquoise usually does not turn green over time. | ZPR |
| Gemstone Terms | ||
| natural | A naturally occuring gemstone that has only undergone the standard process of cutting and polishing. | |
| treated | Gemstones that have undergone dramatic improvements in color, clarity, and/or durability. These processes go beyond what is considered standard. Examples: diffused sapphire, Mystic topaz (CVD), irradiated blue diamond | |
| artificial | The term artificial is a catch-all for any lab-created gem. Artificial gems that have the same chemical, optical, and physical properties as their natural counterparts are more accurately described as synthetic | |
| synthetic | The term synthetic is used to describe a lab-created gemstone that has a natural counterpart. Synthetic gemstones have the same chemical, optical, and physical properties as those occurring in nature. Examples: synthetic sapphire, synthetic alexandrite | |
| simulant/man-made | The term simulant is synonymous with substitute or imitation. A simulant only mimics the appearance of another more expensive gemstone. A simulant usually indicates a man-made material. Examples: red glass (ruby simulant), white YAG (diamond simulant) | |
| lab created | The term lab created is used to describe any material synthesized by man. Lab-created gems with no natural counterparts fall into the category of artificial, and are used as simulants. Lab-created gems that duplicate the properties of naturally occurring | |
| imitation | The term imitation is used to describe any material that mimics the appearance of a natural gemstone. Imitations may be lab created, or natural. Examples: red glass (imitation ruby), white YAG (imitation diamond) | |
| hybrid | A stone with natural and artificial components, where the two cannot be separated. New category created by a new generation of treatments that add materials to a natural base material. In most cases, undesirable elements of a natural material are removed and replaced by added artificial gem material; glass, polymers or synthetic material. Most require special care. | |
| enhanced | A natural gemstone whose color or durability has been improved by an accepted industry-standard practice. Examples: heated citrine, bleached Akoya pearls | |
| color enhanced | Color has been improved by various processes or agents. | |
| clarity enhanced | Clarity has been improved with colorless glass, oil, plastic, resin or some similar substance. | |
| hardness | Hardness is the ability to resist scratching. | |
| toughness | Toughness is the ability to resist breakage (deformation in the presence of external forces). | |
| stability | Stability is the ability to remain unchanged in the presence of heat, light, and/or chemicals. | |
| durability | Durability is defined as a combination of hardness, toughness, and stability. | |
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