Purity, or clarity, depends on the amount (or lack) of inclusions visible with the naked eye or with a magnifying glass.
Clarity is a measure of internal defects of a diamond called inclusions. Inclusions may be crystals of a foreign material or another diamond crystal, or structural imperfections such as tiny cracks that can appear whitish or cloudy.
The number, size, color, relative location, orientation, and visibility of inclusions can all affect the relative clarity of a diamond. The GIA and other organizations have developed systems to grade clarity, which are based on those inclusions which are visible to a trained professional when a diamond is viewed under 10x magnification.
The graduation is as follows :
- IF = LC : Clear as examined under 10x magnification – Loupe Clean (LC) – No trace of inclusions
- VVS1 et VVS2 : Tiny inclusions, hardly visible with x 10
- VS1 et VS2 : Very small inclusions, almost invisible
- SI1 et SI2 : Small inclusions, visible
- P1, P2 et P3 Inclus (included) : Big inclusions/ numerous inclusions, visible with the naked eye.
The image shows the degree of inclusions and imperfections, visible in diamonds, that are used to detemine the degree of clarity of a diamond.
This identification is the most common, because every diamond is unique : it is it’s digital footprint. To do this international symbols are used : the red corresponds to internal flaws, the green to exterior characteristics.
The placement of the inclusions in the diamond’s material is very important for it’s value : an inclusion in the table of a diamond will appear as a bright star. The inclusions are not easily spotted with the naked eye.
Very high purity levels do not increase the visible beauty of a diamond, but has great effect on it’s rarity and therefore it’s price.
In general, diamonds with clarity grades between IF and SI2, do not show inclusions that can be seen by the naked eye.
Also, very high clarity does not automatically mean the diamond is more beautiful. For jewelry, clarity levels above SI are not needed.
On the other side, more clarity is better, more rare and therefore more expensive. In the case of an investment it is therefore strongly recommended to choose a diamond with clarity between IF and VVS2.