Colourless diamonds are the most desirable since they allow the most refraction of light (sparkle). The whiter a diamond's colour, the greater its value. To grade 'whiteness' or colourlessness, most jewellers refer to GIA's professional colour scale. This begins with the highest rating of D for completely colourless and travels down the alphabet to grade stones with traces of very faint or light yellowish/brownish colour. Diamonds graded G through to I show virtually no colour that is visible to the untrained eye. Think about what colour of precious metal you will use for your setting - if you like white gold, palladium or platinum, then we would suggest a higher grade colour for your diamond choice.
NOTE: Fancy coloured diamonds do not follow this rule. These diamonds are very rare and expensive and can be any colour from pink, blue and green to bright yellow.
Most diamonds contain some inner marks (called “inclusions”) that occur during the formation process or in the cutting/polishing process. The visibility, number and size of these inclusions give the “clarity” rating of a diamond. Diamonds that have fewer inclusions create more brilliance and are therefore more highly sought-after (and priced). Diamonds are graded for clarity under 10x loupe magniﬁcation. The following ratings and descriptions will give you an idea of what to look for.
F – Flawless: no internal or external ﬂaws. Extremely rare.
IF – Internally flawless: no internal ﬂaws, but some surface ﬂaws. Very rare.
VVS1-VVS2 – Very, very slightly included (two grades). Minute inclusions very difﬁcult to detect under 10x magniﬁcation by a trained gemologist.
VS1-VS2 – Very slightly included (two grades). Minute inclusions seen with difﬁculty under 10x magniﬁcation.
SI1-SI2 – Slightly included (two grades). Minute inclusions more easily detected under 10x magniﬁcation.
I1-I2-I3 – Included (three grades). Inclusions visible under 10x magniﬁcation as well as to the human eye. We do not recommend buying diamonds in these grades.
Remember that even though some diamonds may have inclusions, this does not make them any less beautiful to look at. Some people decide to choose a larger stone with a SI1-SI2 clarity, while others prefer to have a smaller stone with less inclusions (in the VVS1- VVS2 clarity rating). This is a personal choice and nobody looking at the stone (unless under a jeweller’s loupe) would ever notice the differences.
Cut is probably the most important quality factor and the most challenging of the four C’s to understand. A good cut gives a diamond its brilliance – the brightness that seems to come from the very heart of a diamond. The cut doesn’t actually refer to the shape of the diamond (eg: round, pear, princess, emerald shapes); rather, the angles and ﬁnish of a diamond are what determine its cut and ability to reflect light.
When a diamond is well-cut, light enters through the table (top surface of the diamond) and travels to the pavilion (the bottom point of the diamond) where it reﬂects from one side to the other before reﬂecting back out of the diamond through the table to your eye. This is what gives a diamond its sparkly brilliance and why you can’t take your eyes off one when you wear it!
In a poorly cut diamond, the light that enters through the table reaches the facets (the flat surfaces of a diamond) and then 'leaks' out from the sides or bottom of the diamond rather than reﬂecting back through the table to your eye. Less light reﬂected back to the eye means a less sparkly stone.
There is an interesting story about how this term originated. The word "carat" is taken from the carob seeds that were once used in ancient times to balance scales. These seeds are so alike in shape and weight that even today's sophisticated instruments cannot detect more than three one-thousandths of a difference between them!
A carat is a unit of measurement used to weigh a diamond. One carat is equal to 200 milligrams, or 0.2 grams. Because large diamonds are found less commonly than small diamonds, the price of a diamond rises according to its size or carat. Remember that bigger is not always better; sometimes a ring can look just as magnificent featuring a smaller diamond rather than a large one.
Common Diamond Shapes