At least 13 factors affect diamond value, including fluorescence, table percentage, symmetry and other crucial details.
The most important factors when determining the quality of a diamond are known as the 4Cs.These are the diamond’s carat weight, its cut, its colour and its clarity.
The key thing to note is that no one C is more significant than another. A particular combination of the 4 Cs can be chosen to suit a particular budget, occasion, design or jewellery piece.
Color: stone can be bombarded (i.e. irradiated) by either atomic or subatomic particles; these particles damage the diamond’s internal structure, which may change the color. The longer the bombardment, the more intense the color. Color: The most recent and sophisticated development in diamond colour improvement is to treat brownish coloured diamonds to improve their colour. The colour change is to either colourless or fancy yellow/green depending on the starting material.
Diamonds are found in almost every colour of the rainbow, but white-coloured diamonds remain the most popular.
There are more than 20 subtle grades of colour, identified in alphabetical order from D-Z.
Variations are so slight that colours must be graded by an expert under controlled lighting conditions and compared against a master set for accuracy.
Those at the upper end of the scale will be more expensive, as they are rarer. However, they are difficult to discern with the naked eye
Naturally-occurring features – known as inclusions – provide a special fingerprint within the stone. Usually invisible to the naked eye, these tiny marks are minerals or fractures which appeared while the diamonds were forming in the earth
The number, type, colour, size and position of these inclusions can affect the value of a diamond
Many can only be seen by a 10-power magnification loupe or stronger
Flawless diamonds are rarer and thus more expensive. Small inclusions do not affect the beauty of brilliance of the diamond however
Cut is the shape and cutting style of a diamond.
The cut, polish and proportions of a diamond will determine its appearance.
The shape of a diamond is a matter of personal taste, with the round brilliant cut the most popular. Other shapes are the asscher, cushion, emerald, heart, pear, marquise, oval, princess and trilliant
Sir William Crookes was the discoverer of Thallium, identified the first sample of Helium, worked with Faraday and wrote a great book on Diamonds. He was the first to note the effects of Irridiation on Diamond Color in 1904
In the 1500’s it was believed in India that Diamond dust was a poison (and read how it was proven not to be !) whereas in Europe it was believed Diamonds protected against the plague (and read the hilarious reasons why !)
Hope Diamond: Streeter who supposedly bought part of the original Tavernier Blue diamond, that together with another stone in Geneva would and the Hope diamond would add up to the original blue diamond that was sold to Louis IX by Tavernier.
Also Orpen and Hershey ‘s short factsheet
Kunz on the sale of the Hope to Frankel
List of Famous Diamonds
Great Mogul Diamond
Star of the South Diamond
Du Toit I Diamond
Great Table Diamond