DIAMOND CLARITY - Factors, Scale & Grading

Did you know that of all diamonds unearthed from mines a mere 20% is destined for use in fine jewellery and of them less than 1% is graded as flawless? Underground, during their crystallization, and on their way up, diamonds trap mineral impurities. Extreme pressure and heat often cause anomalies to their structure. These internal characteristics are called inclusions. Nature or human hand can also cause surface flaws; namely blemishes. Diamonds with the least visible defects receive the highest clarity rates and the chilliest price tag. Before shopping for the diamond of your dreams get to know what you are paying for.


Clarity is one of the 4Cs of the diamond grading system of GIA (Gemological Institute of America) that was established in 1953 by the Richard T. Liddicoat team. 

Diamond clarity grading involves determining the quantity, size, and position of the inclusions. It is important to know that a Diamond inclusion grading is not simply a head count of how many flaws there are, but how they affect the overall appearance & light refraction of the stone.


Based on industry terminology and lastly revised in the 1990s, the current scale consists of eleven clarity grades:
Flawless (FL)
Internally Flawless (IF)
Very Very Slightly Included 1 & 2 (VVSI & VVS2)
Very Slightly Included 1 & 2 (VS1 & VS2)
Slightly Included 1 & 2 (SI1 & SI2)
Included 1-3 (I1-3)

Today, each GIA report for a-carat-and-over diamond contains its clarity plot or diagram which is mapping its imperfections, and is used as a reference.


Inclusions visible under 10x magnification affect the grading of a diamond but not necessarily its beauty and desirability. In eye-clean diamonds you cannot see them. In those between VS2 and SI1, your choice depends on various factors. The size and number of the imperfections might lower the clarity grade. If a cloud is oriented in a way that inhibits light transmission, the stone appears less charming too. Inclusions located right under the top facet (table) or in the middle of the crown are often noticeable. If found below the crown facets, they might pass unnoticed. Inclusions near the edges or the pavilion might well be hidden by the setting of a diamond ring. Yet relatively ‘sheer’ internal cracks close to the surface might put the stone at risk of chipping or cracking. Finally, the colour of an inclusion is mostly preferred to be white rather dark and contrasting.


The clarity grading of diamonds ranges from 'IF' (the perfect, internally flawless diamond) down to 'I3' (a stone with many inclusions that are visible even to the naked eye). Inclusions in diamonds can take the form of white 'feathers' that look like little cracks or can be black marks that look like grains of pepper encased in the diamond. The clarity scale is based on how noticeable the inclusions in the diamond are & not how many inclusions. 'VVS1' & 'VVS2' clarity diamonds have inclusions that are so small they can be easily missed even when looking through a jeweller's loupe (a 10 times magnifier). 'VS1' & 'VS2' clarity are still very hard to spot through a loupe whilst 'SI1' & 'SI2' inclusions can be easily found when using a loupe.


Natural diamonds are made from carbon that has been exposed to huge amounts of heat and pressure while deep within the earth. This can result in various types of Diamond ‘inclusions’ (aka ‘flaws’) and external characteristics called ‘blemishes’ or ‘cavities’.

The inclusions are formed when small crystals get trapped inside a Diamond while it is being formed.

The GIA developed the clarity scale that jewellers use today because the terminology used to be a little vague. Phrases like ‘loupe clean’ & ‘pique’ left a little too much to interpretation & so a more accurate clarity grading scale was called for.

The GIA Diamond Clarity Scale has 11 specific grades which are as follows:

Flawless (FL) No inclusions and no blemishes visible under 10x magnification

Internally Flawless (IF) No inclusions visible under 10x magnification

Very, Very Slightly Included (VVS1 and VVS2) Inclusions so slight they are difficult for a skilled grader to see under 10x magnification

Very Slightly Included (VS1 and VS2) Inclusions are observed with effort under 10x magnification, but can be characterized as minor

Slightly Included (SI1 and SI2) Inclusions are noticeable under 10x magnification

Included (I1, I2, and I3) Inclusions are obvious under 10x magnification which may affect transparency and brilliance

Crystal – these are an actual crystal made of another mineral. In some cases these crystal inclusions can be another type of gemstone. So a gem within a gem! Although very rare these crystal inclusions can be peridots or garnets.

Cloud – this is a group of very small pinpoint crystals that are clustered very close to each other. They can sometimes make a Diamond appear misty.

Feather – these inclusions are small fractures within the Diamond. Small feathers are usually fine but very large ones can cause the Diamond to chip.

Twinning wisp – these are groups of other inclusions that you will see in this list. They can be clusters of pinpoints, crystals or clouds. They are caused when the crystal of Diamond with stunted growth starts to regrow in a different direction. This can occur thousands of years after the stone started to originally form.

Needle – as the name suggest needles are a long, thin Diamond inclusion.

Pinpoints – again, as the name suggest, these are tiny dot like inclusions. That can be black or white.

Cavity – this is a crevice in a Diamonds surface. Cavities are internal inclusions that break the surface of a Diamond. 

Bearding – hair like likes that look like scratches. These often occur when & Diamond is cut & polished.

Graining – these appear like faint lines & are caused by a Diamond with irregular crystal growth.

Chip – just as it sounds this is simply a damaged Diamond. When sent to a laboratory for grading a chip will be treated just like an internal inclusion. 

Indented natural – not to be mistaken for a chip this is a part of a Diamond that is left from its natural, rough state. It remains unpolished because it sits below the surface of the rest of the Diamond.

Knot – knot inclusions can appear either white or clear. They are a type of crystal that reached the very surface of apparent Diamond.