Diamonds can be cut in various shapes like the most commonly used in jewellery the round brilliant cut.
The proportions are determinative for the brilliancy and the fire of the diamond. The symmetry describes the variations of the different parameter which define the proportions. The polish describes the finish of the facets.
The majority of white diamonds are colourless to faintly yellowish taint. The more colourless the diamond the higher the value, the colour grade determined by comparison with a series of master stones.
Diamonds can also come in a variety of colours, ranging from brown to yellow, from pink to purple, from red and blue. These are known as ‘’Fancy Colours’’, these have a different way of grading from the white diamond.
Certain diamonds can react to ‘’Black Light’’ with grades measuring from nil, slight, medium to strong. Besides the colour the fluoresce of the diamond is also graded.
All diamonds have traces of their development history. In gem-quality diamonds, this is concerns minute internal and external characteristics, grade under clarity.
The clarity scale reveals the size, number, location and visibility of the characteristics when examined with a loupe 10x. The very best and rarest clarity is loupe clean. Most inclusions, however, are not visible to the naked eye. Diamonds that have no inclusion visibility are also of excellent value.
The weight of a diamond is expressed in the diamonds carat. One carat is equal to 0.2 grams and one carat equals 100 points.