The concept of the 4 C's (Cut, Colour, Clarity and Carat Weight) is used Internationally in order to group the specific characteristics for Diamonds.
Cut enables a Diamond to make the best use of light. A well cut diamond is the work of a master Diamond Cutter. When cut to good proportions, a diamond will handle light better resulting in more brilliance. A well cut Diamond occurs when light enters through the crown and is reflected from one facet to another and then dispersed through the top of the stone. (Diagram A) If the Diamond is cut too deep, some of the light entering the diamond is reflected but escapes through the pavilion. (Diagram B) If the Diamond is cut too shallow, some of the light entering the Diamond escapes through the pavilion before it can be reflected. (Diagram C)
| Ideal | : Diamonds cut to "Ideal" proportions. Maximum beauty is yielded with these proportions. |
| Very Good | : Diamonds cut just very slightly outside of "ideal" proportions. |
| Good | : Diamonds cut noticeably outside "ideal" proportions but above average. |
| Medium | : Diamonds cut to average proportions with somewhat noticeably reduced brilliance. |
| Fair | : Diamonds cut to somewhat below average proportions with reduced brilliance and noticeable cutting flaws. |
| Poor | : Diamonds cut well below average proportions with distinctively reduced brilliance and noticeable cutting irregularities to the untrained eye. |
Colour contributes to the value of a diamond. Diamonds are found in a wide range of colours. It is the absence of colour that makes a diamond more valuable and rare (with exception to "Fancy Coloured" diamonds). The Gemological Institute of America (GIA) colour grading scale begins at colourless and ends at fancy yellow. Diamonds are colour graded according to the amount of colour saturation present in the diamond. The difference between one colour grade to the next grade is very subtle.
Clarity is the extent to which a Diamond has or is free of any inclusion(s). Inclusions are none other than a Diamond's natural occurring fingerprint that makes each diamond unique in itself. A Diamond is Clarity graded under ten power (10X) magnification and is assigned a Clarity grade based on the Gemological Institute of America Clarity grading System.
A Flawless grade is given to a diamond in which a qualified gemologist cannot find any inclusions and finishing faults.
Very, very slightly included and may have very slight surface blemishes.
Very slightly included. Inclusions are difficult for a qualified gemologist to locate.
Slightly Included. An SI1 or SI2 clarity grade is given to a diamond which has an internal inclusion(s) or external blemishes that can be located without difficulty by a qualified gemologist.
Internal inclusions or external blemishes that can be located with the unaided eye by a qualified gemologist.
The weight or size of a diamond is measured in carats (ct.). A carat is 0.2 grams and there are 100 points (or 200 milligrams) per carat. With an accuracy of 1/100,000 ct, the IGI. scales provide a highly precise diamond weight and this weight is specified on the Diamond Report to two decimal points.
