When diamonds are assessed and certified, their basic parameters are evaluated--the so-called 4Cs: cut, clarity, colour and carat. These properties significantly influence the price of a diamond.
CUT: The right cut gives a diamond its radiant lustre. The most popular cut is a round cut, the so-called brilliant. Diamonds can also be cut into a wide array of so-called “fantasy” cuts, e.g. marquise, baguette, heart, tear, oval or princess (a four- or three-sided cut with sharp corners, popular especially for engagement rings.
CLARITY: Clarity determines the number, size and distribution of so-called “inclusions”, or internal impurities of a diamond:
- IF (Internal Flawless) – diamonds with absolute transparency without inclusions,
- VVS 1, VVS 2 (Very, Very Small) – diamonds with very small inclusions,
- VS 1, VS 2 (Very Small) – diamonds with small inclusions,
- SI 1, SI 2 (Small Inclusions) – diamonds with inclusions which can be detected with a magnifying glass,
- I1, I2, I3 (Included), also labeled P in the Czech Republic – diamonds with medium to larger inclusions visible to the naked eye.
COLOUR: The colour of white to yellow diamonds is evaluated according to an international scale:
- D to F – colourless diamonds;
- G to J – nearly colourless diamonds;
- K to M – diamonds with yellow tones;
- N to Z – diamonds with yellow-brown hues.
Other colours are simply called fancy. Some of our colourful diamonds are treated to emphasise their colour.
CARAT: The carat (ct) is the diamond’s unit of weight, expressed to the second decimal place, e.g. 0.25 ct. 1 ct = 0.2 g. For jewellery with multiple diamonds and for earrings, we always state the total number of carats of all diamonds.