Which has comparison as follows :
AAA (A3) : 4 stars.
AA (A2) : 3 stars.
BA: 2 stars.
C : 1 star
Color: |
 |
Very exelent quality for beads standard |
 |
Very beautiful, but not the most popular color | |
 |
Common as you will see in the market | |
 |
Not constant color in one string. Sometimes mixed color. | |
Cutting: |
|
Good shape. Cut beatutifully by machine. |
|
||
|
Cut beautifully. But the hole might not be straight or the hole edge might not be beautiful. | |
|
Not beautifully cut. The shapes might not be very round or not be symmetrically. Looks like cut by hand. | |
Clarity: |
|
Very good |
|
||
|
||
|
Not very good. Contains a lot of inclusion. Looks cloudy. |
| N | Not enhanced. The stone has received no enhancement and the seller will provide a guarantee that there has been none. |
| B | Bleaching: The use of chemicals or other agents to lighten or remove a gemstone's color. |
| C | Coating: The use of such surface enhancements as laquering, enameling, inking, foiling, or sputtering of films to improve appearance, provide color or add other special effects. |
| D | Dyeing: The introduction of coloring matter into a gemstone to give it new color, intensify present color or improve color uniformity. |
| F | Filling: As a by-product of heat enhancement, the presence of solidified borax or similar colorless substances which are visible under properly illuminated 10X magnification. |
| G | Gamma/Electron Irradiation: The use of gamma and/or electron bombardement to alter a gemstone's color; may be followed by a heating process. |
| H | Heating: The use of heat to effect desired alteration of color, clarity, and/or phenomena. (Residue of foreign substances in open fractures is not visible under properly illuminated 10X magnification.) |
| I | Infilling: The intentional filling of surface breaking cavities or fractures usually with glass, plastic, resin with hardeners and/or hardened foreign substances to improve durability, appearance and/or add weight. |
| L | Lasering: The use of laser and chemicals to reach and alter inclusions in diamonds. |
| O | Oiling/Resin Infusion: The intentional filling of surface breaking cavities with a colorless oil, wax, natural resin, or unhardened man-made material. (Oil, man-made resin, cedar wood oil, Canada balsam, paraffin, etc.) |
| R | Irradiation: The use of neutron, requiring an environmental safety release from the Nuclear Regulatory Commission, with the combination of any other bombardement and/or heat treatment to alter a gemstone's color. |
| S | Bonding/Stabilization: The use of colorless bonding agents (commonly plastic) within a porous gemstone to give it durability and improved appearance. |
| U | Diffusion: The use of chemicals in conjunction with high temperatures to produce color and/or asterism-producing inclusions. |
| W | Waxing/Oiling: The impregnation of a colorless wax, parafin and oil in porous opaque gemstones to improve appearance. |
| Category of synthetic stones | |
|---|---|
| SYN | Synthetic materials. The name synthetic must be accompanied by a specific reference to the actual composition. |
| IMIT | Imitations, product-simulants, subsitutes. Trade names used to promote various simulant products in these category must be accompanied by a specific reference to the actual composition of the simulant. |
| ASBL | Assembled materials, composite, doublets, triplets. Tag for products of multiple layers or combinations of manufactured and/or natural materials fused, bonded or otherwise joined together to increase stability and/or to imitate the appearence of a natural gemstone, create a unique design or generate unusal color combinations. |
The above codes and explanations were taken from the American Gem Trade Association's AGTA Source Directory 2000-2001.