Those who are not really expert can confuse a little between diamond and brilliant . The first is the rough stone ; the second is the stone cut and worked following the criteria of a particular type of cut called " brilliant " which restores the maximum brightness to the stone itself.
The worked diamond is subjected to an accurate gemological analysis, after which it is assigned an exact qualification from which it derives a certain commercial value.
The value of a diamond is defined on the basis of four classification parameters, namely the famous 4 Cs from the initials of the terms in English:
Carat ( Weight )
The weight of diamonds is expressed in carats (1 carat = 0.20 grams). The carat in turn is divided into cents called " points ".
Clarity ( Purity )
Pure diamonds are considered to be those cut diamonds which, observed with a 10 magnification lens , do not show any inclusion.
The crystal lattice of the diamond often presents interruptions that may depend on crystalline inclusions, cavities, cracks, twinning planes, structure lines, cleavages and internal tensions.
In Germany and Italy, the term purity means internal perfection, while in the USA and Scandinavia external characteristics are also taken into consideration.
In Europe and the United States the clarity of a diamond is measured using the following scale ( called GIA ):
IF or LC
(internally flawless or loup clean) = pure to the lens, free from internal characteristics at 10x.