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How is diamond value determined?

Diamonds have been catching the eye with their unique glow and beauty for centuries. Diamonds are not only fantastically beautiful – diamonds are also one of the rarest natural minerals in the world.

The main features of the diamond:

  • Hardness: The diamond can not be scratched by anything other than the other diamond.
  • Brightness or luminosity: Diamonds have the highest brightness, that is why they are called “adamantines”.
  • Brilliance: is a light effect produced by the number, size and location of the faces.

4 basic determinants of the diamond, which determine its final value (4 C: carat weight, colour, clarity grade, cut grade):

  1. Cut
  2. Colour
  3. Clarity grade
  4. Carat weight

CUT (cut grade/make)

The upper picture shows a variety of cuts and how the light reflects in them. The ideal and good cuts are the options that can be recommended when you buy a stone, in both cases the light is reflected back, which makes the stone beautifully shining.

The bottom picture shows a Good diamond cut in percentages with degrees of angles. This does not mean that only these values are valid. The correct numbers are everything that remain between the ideal and good cuts.


The cut does not indicate the shape of the diamond, but diamond’s proportions, symmetry and polishing. The beauty of a diamond depends the most on the cut (secondly, the colour and then the purity) than any other factor. Diamond proportions refer to the ratio of faces to size, shape and angles. Different combinations are possible, which ultimately determine the diamond ratio for light reflection.


Different shapes


Colours G and H are the most common ones – these colours have a good price and quality ratio.

Clarity grade

Higher quality from left to right.


FL – Flawless. Completely flawless.

IF – Internally flawless, some minor surface defects, that can be removed by polishing.

VVS1 – VVS2 – Very, very slight inclusions, barely noticeable with 10x magnifier, small surface defects.

VS1 – VS2 – Very slight inclusions and surface defects, easily noticeable with 10x magnifier, but that are hardly noticeable with bare eye.

SI1 – SI2 – Slight inclusions and surface defects, easily noticeable with 10x magnifier, but that are hardly noticeable with bare eye.

I1 – Inclusions are visible with naked eye, but do not affect the brilliance. Noticeable surface defects.


The crystal lattice of the diamond is formed from carbon atoms and its weight unit is carat (deriving from the Ancient Greek word ‘keration’, meaning the carob bean used for very small amounts in weights) equal to 0.2 grams.

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Diamonds were discovered about 4,000 years ago (their formation began already billions of years ago).

The word “diamond” comes from two Ancient Greek words: “adamas” (unbreakable, tameless) and “diaphanes” (transparent) referring to eternal love. From Ancient Greece, diamonds and diamond jewellery have traditionally been considered symbols of love.

Already Pliny the Elder (I century BC) writes in his encyclopaedia “Natural History” that diamonds are considered to be the hardest stones found at all. Due to its properties, the diamond has become a symbol of strength.

In order to crystallize into a diamond, the carbon atoms must be at least 150-200 meters below the ground or at a pressure of at least 50 kbar and at a temperature of 900-1200 degrees Celsius.

Diamonds come to the ground together with kimberlite magma due to geothermal movements within the Earth. Later, however they move around with floodwaters or instead, converge to some areas.