Every diamond is unique and has its own specific set of characteristics which define its value. Diamonds are graded according to the four basic criteria, the so called 4Cs. Cut, Carat, Colour and Clarity.


Cut is considered the most important of the criteria because it affects the overall appearance of the diamond, as well as its size and ability to reflect light. More than any other factor, this decides the beauty of the gem. There are several types of diamond cuts and we will introduce some of them.


The most popular and most sparkly of cuts. This cut enables almost 98 % of the light that lands on the surface to be reflected. Such diamonds have an unbelievable brilliance and lustre and that is why they are often called brilliants.


Second favourite after the round cut and also very popular, specific with its angular parallel shape and consists of usually 57 or 76 facets. It is mostly used for engagement rings, solitaire rings or earrings.


This shape of diamond belongs to stepped cuts and is often used to polish emeralds, which is why this technique is often called emerald polish. It is of a rectangular shape, with cut corners and a flat table. 


Pear or teardrop diamond shape Is usually used for earrings or pendants. The shape of the pear optically extends fingers, but also stands out on even slender fingers. 


In recent times, the so called cushion cut is becoming ever more popular. It is either rectangular or square shaped with rounded corners. The rectangular variety of this cut has 70 facets, with the emphasis on brilliance.


Colour in diamonds is another foundational criteria. The less colour the ‘colourless’ diamond has, the higher the value. Natural diamonds also occur in many colours, from totally colourless through light yellow to rich yellow. Colour is graded on a scale from D-Z, where D-F are colourless, G-J are nearly colourless, K-M are very slightly tinted, N-R are slightly tinted, S-Z are visibly tinted.

Coloured diamonds are classified with a different scale. They are assigned with the true colour of the gem and we recognise two characteristics, colour and intensity.

There are 12 different main colours, when it comes to coloured diamonds, which can contain one identifiable colour, or can be combined with up to 2 modifying colours.

The level of the colour intensity can be from a slight tint, up to very rich in colour. The richer the colour, the higher the value of the diamond.



Carat is a unit which is used to measure the weight of a diamond. Abbreviated as ct. One carat represents one fifth of a gram (200mg). The weight considerably affects the price of the stone.

The price of a diamond is often expressed as price per carat (ppc), instead of an actual unit price for the stone.


With regards to the clarity of diamonds, one can say that all stones have some inclusions. Sometimes they are so small and negligible that even with 30x enlargement it is almost impossible to identify them. Often these imperfections are better hidden in coloured diamonds. The way inclusions affect the value of the diamond depends on the size and type of the inclusion, but also on which part of the stone they are found. With increasing number of inclusions, the value of the diamond decreases accordingly.

The clarity of diamonds is divided into the following categories:

IF - (Internally Flawless) Diamond contains no inclusions and is at the highest level of clarity.

VVS 1 and VVS 2 - (Very very Slightly Included 1/2) Diamond contains very very slight inclusions which are hard to identify, often good as investment diamonds. 

VS 1 and VS 2 - (Very Slightly Included 1/2) Under 10x magnification, a qualified gemologist is able to identify small inclusions which are difficult to see with the naked eye.  A non experienced observer would be unlikely to identify such inclusions.

SI 1 and SI 2 - (slightly Included 1/2) The diamond has visible inclusions under 10x magnification which could also possibly be seen with the naked eye.

I 1 - (Included 1) Inclusions are, with some exceptions, visible with the naked eye, but do not affect the lustre and sparkle of the diamond.

I 2 - (Included 2) Inclusions are always visible with the naked eye and affect the brilliance and lustre of the diamond,

I 3 - (Included 3) The diamond contains numerous cracks, faults and inclusions, which considerably affect the lustre and sparkle of the diamond.  These diamonds can potentially crack when set.



At Korbicka jewellery, we work with high quality GIA or IGI certified diamonds and gems. The Gemological Institute of America (GIA) is a non profit organisation and the most recognised world institution for certifying diamonds, gems and pearls. In the 1940s, the GIA set the system of grading diamonds, the so called 4Cs, which set a worldwide trend for other companies and it is still used until today. The International Gemological Institute (IGI) also stands as one the leading laboratories grading the quality of diamonds and gems. For some diamonds and gems, we also create our own certificates, according to the specific characteristics.