Carat is a measure of weight. One carat (1 Ct) equals 0.20 grams and is divided into 100 points (a half carat diamond – 0.50 Ct – can also be described as a 50 point diamond). Although weight plays a major role in determining value, clarity, colour and cut must also be considered.
Cut is the factor most involved in the sparkle of a polished diamond and is expressed in terms of the brilliance, fire and scintillation of a diamond. To maximise sparkle, a diamond must be cut to very specific parameters for angle and dimension with a strict attention to the polished finish of the diamond. A well-cut diamond gathers and concentrates light from many directions, then radiates it outwards to dazzle the eye of beholders.
Colour Diamonds occur naturally in a wide variety of colours. Generally, the rarest diamond’s exhibit no colour at all. A polished diamond is graded for minute variations in depth of colour, from ‘colourless’ to ‘light yellow’ and ‘light brown’. This is universally known as the D (‘exceptional white’) to Z (‘tinted colour’) colour scale.
Clarity measures the diamond’s purity. Naturally occurring features known as inclusions and provide a special fingerprint within the diamond. Almost all diamonds have clarity characteristics. The fewer or less prominent these characteristics the higher the clarity grade.