As a result of discussions between the World Federation of Diamond Bourses and the International Diamond Manufacturers Association on one side and the CIBJO Commission on the other, the gemological Institute of America (GIA) has recently accepted the traditional European term "internally flawless" and has allocated it a place below "flawless" in the clarity scale. With this, the basic agreement between both systems has been achieved.
The GIA has strengthened its acknowledgment of the CIBJO nomenclature at the South African Congress in May 1980.
The term flawless is interpreted by the GIA as follows: Cut diamonds are termed flawless if no infernal or external defects can be seen under a 10 x magnification. Excepted are the smallest external faults, as extra facets or naturals, which are not larger than the widest part of a fine girdle, and which do not in any way influence the symmetry of the' girdle nor are visible through the crown.
A diamond is internally flawless if it is free from
internal faults under 10 x
magnification. Certain external faults are allowable: small polishing
marks,
which can be removed with a minimum loss of weight, extra facets and
naturals also above the girdle. Further larger external faults influence
the clarity grade.
The scale then is as follows:
| very, very slightly included | VVS 1+2 |
| very slightly included | VS 1+2 |
| slightly included | SI 1+2 |
| imperfect 1-3 | I 1-3 |
| Scan.D.N. | IDC |