The quality of a diamond is determined by the
four C's. Carat, Colour, Clarity and Cut.
What is a carat?
Diamonds are weighed in carats.
One carat equals a fifth of a gram. The name "carat" comes from
a seed of the carob tree. The seed was called "carubis" and had
an approximate weight of about 0.2 grams.
How is the color of a diamond measured?
Colour is graded by comparison to
masterstones under standardized artificial light, equivalent to
Indicated colours are only meant to show the difference in
How is the clarity of a diamond measured?
A diamond is "loupe clean or
internally flawless" if, after examination by an experienced
grader with a loupe 10 x under normal light conditions, it has
been found free of internal characteristics. The other clarity
grades are determined by the size, position, brightness and
number of internal characteristics. External characteristics and
structure phenomena can be mentioned under "identification
marks" or "comments". The lowest clarity grades on the scale (indicated
by p for piqué) refer to inclusions that can be seen by an
experienced grader with the naked eye.