shape
Carat is the weight unit for diamonds. 1.00 carat equals 0.20 grams
Colour
One of the fundamental 4Cs: the less colour a diamond has, the greater its value. The GIA scale runs from D (perfectly colourless) to Z (heavily tinted yellow).
Clarity
Measures the presence of internal inclusions or surface blemishes. The purer the diamond, the more light passes through it and the higher its value.
IGI, GIA and HRD are the most reliable certificates.
Polish
Describes the quality of finish on the outer surface of the diamond. A high grade maximises light reflection and brilliance.
Symmetry
Evaluates how precisely the facets align and intersect. Minor asymmetries can affect light travel and brilliance. Excellent and Very Good are recommended.
Fluorescence
About one third of natural diamonds emit a completely harmless bluish glow under UV light. Fluorescence rarely affects appearance; in very rare cases it may cause a slight milky effect.