Guide to diamond selection

There are four factors that determine the quality of a diamond:

• Cut
• Size
• Purity
• Color

CUT

The Cut is what gives the stone its ultimate characteristics of brilliance and luminosity. In fact, the light refraction through the faces of the diamond depends on a precise balance between the faces. The cut is thus governed by a balanced interplay of proportion and symmetry, polish and geometric harmony.

Cuts can vary in shape and number of faces. 

The diamond par excellence, which is usually referred to by the collective imagination as the diamond, is the “classical” diamond with 58 faces. The proportions and angles of the faces allow the stone to shine to its fullest: this is the diamond cut.  

There are other cuts that define different shapes, whose common element is to enhance the stone’s ability to reflect light and maintain size. Among the main ones are.

• The Princess cut, square in shape.
• The Baguette, rectangular in shape.
• The heart cut.
• The oval cut. 
• The antique or cushion cut. 

SIZE

The Size is related to the weight of the diamond: the carat. As much as it is one of the most conspicuous and important characteristics, size participates among others in defining the value of a stone: a larger diamond, therefore with higher carat, is not necessarily of higher value. Purity and color are equally important characteristics in sanctioning the quality of a diamond. Therefore between two stones of equal carat weight, the value can be significantly different depending on other factors. 

PURITY

Purity is defined by the natural inclusions contained within the mineral. The smaller the number and size of these imperfections, the higher the diamond’s pureness grade will be.
A scale is used to classify these imperfections, rated on the basis of how visible these inclusions are with a 10X magnification lens.

IF – Internally flawless . No visible flaws

VVS1 – VVS2 – Very Very Very Slightly Included. Very very small inclusions and difficult to identify with 10 X lens

VS1 – VS2 – Very Slightly Included. Very small and hardly identifiable inclusions with 10 X lens

SI1 – SI2 – Slightly Included. Small and identifiable inclusions with 10 X lens.

I1 – I2 – I3 -Included. Inclusions extensive and visible to the naked eye.

COLOR

Color is an important index of diamond quality: the natural variation in color that light takes as it passes through the stone confers preciousness or otherwise. Stones tending toward noncolor or blue are the most valuable. Conversely, the more they tend toward yellow, the lower their value. 
Gli occhi esperti possono essere in grado di identificare accuratamente il colore. Esistono inoltre appositi strumenti in grado di definirlo al meglio. La scala che si usa per la colorazione dei diamanti è espressa in lettere.