DIAMOND 4 C's
Because diamonds are so valuable, it's essential to have a universal grading system for comparing their quality. This comes under the 4 C's,
Carat, Colour, Clarity and Cut.
The Carat of a diamond is how we measure the weight. Just as a pound is divided into 100 pennies, a carat is divided into 100 points. For example, a 50 point diamond weighs 0.50ct. Two diamonds of equal weights can have very different values depending on the other members of the 4C's: clarity, colour and cut. The majority of diamonds used in fine jewellery weigh 1.00ct or less.
Diamond colour is all about what you can't see. Diamonds are valued by how closely they approach colourlessness - the less colour, the higher the value. The exception to this is the fancy-colour diamonds, such as pinks, blues, which lie outside this colour range.
The scale begins with the letter D, representing colourless, and continues with increasing presence of colour to the letter Z, or near-colourless. Each letter grade has a clearly defined range of colour appearance. Diamonds are colour-graded by comparing them to stones of known colour under controlled lighting and precise viewing conditions.
Diamond clarity refers to the absence of inclusions and blemishes. Diamonds without these birthmarks are rare and rarity affects the diamond's value. Diamonds are assigned a clarity grade that ranges from Flawless (FL) to diamonds with obvious inclusions (I3).
Every diamond is unique. None are absolutely perfect under 10x magnification, though some come close. Known as Flawless diamonds, these are exceptionally rare and most jewellers have never seen one.
Though extremely difficult to analyze or quantify, the cut of any diamond has three attributes: brilliance (the total light reflected from a diamond), fire (the dispersion of light into the colours of the spectrum), and scintillation (the flashes of light, or sparkle, when a diamond is moved).
The standard round brilliant is the shape in most diamond jewellery. All others are known as fancy shapes. Traditional fancy shapes include marquise, pear, oval and emerald cuts. Heart cushions, triangles and a variety of others are also gaining popularity in diamond jewellery.