Diamond Grading Terminology
The 4 C's to consider when buying a diamond?
Gemmologists and jewellers assess the physical attributes of diamonds using the 4Cs classification system – cut, carat, colour and clarity.
The 4Cs classification enables the comparison and valuation of diamonds. No one 'C' is more significant than another, and none will diminish in value over time.
A diamond’s beauty is based on far more than these characteristics. Each one was formed billions of years ago and has travelled a long and arduous journey from deep within the Earth. And while most of a diamonds’ qualities are defined by nature, it takes a master craftsman to unlock the diamond’s true brilliance, fire and beauty.
Refers to the angles and proportions of a diamond.
Diamonds are cut in many fancy shapes, i.e. navettes, baguettes, pears, or emerald-cuts etc, however the classic is the round brilliant of eightfold symmetry. The cut refers to the symmetry and proportions of the stone, which directly affects the brilliance or sparkle of the diamond. The maximum brilliance is not only the result of the practical experience and masterly craftsmanship of the cutter, which is needed, but rather the knowledge and application of physico-optical law, in developing and optimal form cut.
Refers to the degree to which a diamond is colourless.
Colour is one of the most characteristics of a diamond which strikes the human eye most strongly, and is produced by the absorption of light. The colour palette is richly varied and ranges from pink through red, blue, green, yellow and brown to even black diamonds. The rarest colour is red, followed by green, blue, purple and brown. These fancy colours, because of their rarity are held in very high esteem, especially when the colour displays an intense saturation. The most valuable diamonds, however, are the completely colourless stones – in this respect diamonds is the only gemstone whose colourlessness renders it more valuable.
Refers to the presence of inclusions in the diamond.
The small internal imperfections in diamonds are known as inclusions. The inclusions which occur naturally are of many shapes and yet very characteristic. Inclusions are proof of the natural origin and should not be regarded as blemishes. The fewer the inclusions the more valuable the stone. The clarity grade is determined by the number, size, nature, and location of the internal (inclusions) and external (blemishes), imperfections.
Refers to the weight of the diamond and not the size.
Besides colour, clarity, and cut, weight provides a further basis in the valuation of a diamond. The weight of all gemstones is measured and counted in carats. A carat is subdivided into points (0.01 carat = l point). One carat is equal to 0.20 grams.