Diamonds are weighed in carats. One carat corresponds to 1/5 of a gram.

The color classification is performed through the use of a color scale.

D exceptional white +
E exceptional white
F extra white +
G extra white
H white
I-J slightly coloured white
Da K a Z coloured with different intensities.

The scale divides the colors into 10 different letters starting from the letter D which identifies the completely colorless and transparent gems (exceptional white +) up to the letter Z (colored stone). In addition to the letter Z, the stones are cataloged as FANCY (fantasy) which go beyond the traditional color classification and receive various evaluations and quotes.

Almost all diamonds have structural inhomogeneities or small crystals of different nature and these imperfections are called “inclusions”. To influence the quality of the stone it is not only the more or less consistent presence of these inclusions but also the color, the number and the size of the same. There is a scale of reference for the classification of the clarity of the diamond that divides the different diamonds according to the characteristics of the inclusions just mentioned:

FL No internal or external inclusion visible at 10x magnification by an expert eye. Maximum level of purity (these are the rarest and most precious stones)
IF No internal or external inclusion visible at 10x magnification by an expert eye. There may be very small imperfections external to the finish.
VVS-1 There is one very small inclusion visible at 10 magnifications only by expert eyes.
VVS-2 There are very small inclusions visible at 10 magnifications only by expert eyes
VS-1 Very small inclusions visible at 10 magnifications.
VS-2 Small inclusions visible at 10 magnifications.
SI-1 / SI-2 More numerous inclusions always visible at 10 magnifications.
SI-3 Inclusions visible to the naked eye only by an expert observer.
I-1 Inclusions visible to the naked eye
I-2 Many inclusions visible to the naked eye and which have a negative impact on the luster of the stone.
I-3 Many inclusions visible to the naked eye which in addition to having a negative impact on the brilliance of the stone also influence its structure, making it more fragile.

The cut is a characteristic of the stone which compared to the others is directly attributable to the influence of man. The different cut has a direct influence on the brightness and brilliance of the stone. Regarding the cut, two distinct considerations can be made:

one linked to the shape that is given to the stone, in this sense we can identify cuts such as:

One linked to the proportions of the cut, which are essential because they determine the different degrees of sparkle of a diamond regardless of the shape. From this point of view we can identify:

Ideal cuts (Excellent)
Diamonds cut with perfect proportions. These diamonds have the highest levels of shine and symmetry.
Optimal cuts (Very Good)
Diamonds cut with proportions that exactly match the requirements required to emphasize the fire and brilliance of the diamond
Good cuts (Good)
Diamonds cut with good proportions but not ideal. They have a good level of brilliance and fire and are still excellent quality jewels.
Poor or Fair cuts
Diamonds cut with proportions that move away from ideal ones. Stones that have less brilliance and sparkle.
Mediocre cuts
Diamonds cut with proportions that make them appear lackluster.

The guide to the perfect diamond

The quality of a diamond is influenced by 4 characteristics (the 4 C): the weight (Carat), the Color, the purity (Clarity), the Cut.

Weight

Color

Purity

Cutting