Diamond Education

Colour

Although many people think of gem quality diamonds as colourless, truly colourless diamonds are actually very rare. Most diamonds we use in our jewellery are colourless.

Colour grades are determined by comparing each diamond to a master set. Each letter grade represents a range of colour and is a measure of how noticeable a colour is.

Clarity

Because diamonds form under tremendous heat and pressure, it is extremely rare to find a diamond that lacks any internal and external characteristics. These characteristics are a by-product of its formation and help gemologists separate natural diamonds from synthetic and simulants, identifying individual stones.

Cut

A polished diamond’s beauty lies in its complex relationship with light. The magnificent display you see is made up of three attributes:
Brightness is the combination of all white light reflection from the surface and interior of a diamond.
Fire describes the “flares” of colour emitted from a diamond.
Scintillation describes the pattern of light and dark areas and the sparkle you see when the diamond, the light, or the observer moves.

A diamond's proportions affect its light and performance, which in turn affects its beauty and overall appeal. Diamonds with fine proportions, symmetry, and polish optimize their interaction with light and have increased brightness, fire and scintillation.

GIA assesses these factors for standard round diamonds in the D-to-Z colour range.

Carat

One carat equals 200 milligrams in weight.

For diamonds under one carat, each carat is divided into 100 points  - similar to pennies in a dollar. 0.75ct, = 75 points, 1/2ct, = 50 points.