The 4 Cs

No two diamonds are exactly alike. Each one is unique. This is why over the years a universal standard for identifying diamonds has been set. The quality and value of a diamond is defined according to the 4 Cs: carat, colour, clarity and cut. At HRD Antwerp we are experts in analysing these characteristics, making sure consumers know exactly what kind of diamond they are buying.

Learn everything you need to know about the 4 Cs in our interactive showcase.

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1
Carat

The weight of a diamond is expressed in carats. One carat equals 0.2 grams or 100 points, which indicates the size. HRD Antwerp has extremely accurate scales that measure up to 1/100,000 of a gram. This accurate weight is very useful for the identification of the diamond.

10 mg
0.05
20 mg
0.10
30 mg
0.15
40 mg
0.20
50 mg
0.25
100 mg
0.50
150 mg
0.75
200 mg
1.00
250 mg
1.25
300 mg
1.50
350 mg
1.75
400 mg
2.00
500 mg
2.50
600 mg
3.00
800 mg
4.00
1000 mg
5.00
1400 mg
7.00
 
2
Colour

Most diamonds range in colour from colourless to slightly yellow. The colour grade is determined by comparison with a series of master stones, the best grade being colourless - a perfect diamond has no colour at all (D Colour: Exceptional White +). Diamonds can also occur in all ranges of colours, from brownish to striking yellow, pink, purple, red, blue and green. These are called 'fancy colours'. Some diamonds react to UV-light (black light) with a grading scale for fluorescence, which ranges from 'nil', 'slight' or 'medium' to 'strong'.

Exc. White +
D
Exc. White
E
Rare White +
F
Rare White
G
White
H
Slightly Tinted White +
I
Slightly Tinted White
J
Tinted White +
K
Tinted White
L
Tinted Colour
M
Tinted Colour
N-O
Tinted Colour
P-R
Tinted Colour
S-Z
 
3
Clarity

With clarity, we describe a diamond's purity. As they are a product of nature, all natural diamonds have traces of their growth history. In gem quality diamonds these are minor internal characteristics. The clarity scale reflects the size, number and location of the characteristics when examined with a 10 x loupe. Diamonds that have no inclusions visible to the naked eye are of excellent quality. The very best - and rarest - clarity is called 'loupe clean'. This means that upon examining the diamond with a loupe, no inclusions can be found.

LC
VVS1
VVS2
VS1
VS2
SI1
SI2
P1
P2
P3
4
Cut

A diamond's cut is essential to its beauty. The cut is divided into 3 grades: proportion, polish and symmetry. Proportions determine the brilliance and 'fire' of a diamond, symmetry describes the variation of different parameters that define the proportions and polish describes the finish of the facets. Each grade is evaluated according to four parameters: Excellent, Very Good, Good and Fair. If the diamond is not well cut, it will not interact with light as it should. A perfect cut equals more sparkle, brilliance and fire.

Proportions

Proportions

Polish

Polish

Symmetry

Symmetry
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