A diamond's weight is measured in carats and is the key driver of value, along with quality. A carat was traditionally an imperial measure of weight but today refers to 1/5th of 1 gram. It takes on average 200 tonnes of diamond bearing rock to mine 1 Cts of diamonds. The larger the diamond, the rarer it is still so the value of a diamond goes up exponentially with size.
The natural qualities of a diamond are only truly brought to life once its rough edges have been cut into symmetrical facets. Master craftsmen seek to bring the best out of the rough diamond, maximising the refraction and reflection of light within each unique stone. Modern equipment and techniques have enabled the standardisation of a wide range of shapes and styles, ensuring the facets are cut proportionally and symmetrically. Others prefer traditionally cut antique stones for their unique personality. Regardless of the shape or style, an expertly cut diamond will sparkle all the brighter.
Diamonds are graded alphabetically according to their colour from D to Z, with the purest white diamond a D. The "collection colours", D, E & F are used by the most exclusive jewellers, with G & H still regarded as white and considered high quality. Colours from I and down, start to show a light tint of yellow, becoming more apparent until the stone starts to gain such a strong colour it can be considered fancy coloured. As the colour becomes increasingly intense or vivid the diamond becomes rare again and high prices can be demanded.
Fancy colour diamonds are most commonly yellow. Rarer colours like pink, blue, green and red are extremely rare and can fetch prices into the millions!
Most diamonds are not perfectly clear crystals, containing impurities called inclusions within the stone. Only stones that contain no visible impurities under 10X magnification can be considered "Flawless." These are exceptionally rare and command the highest prices. There is a descending scale to classify the diamonds according to the size, number and location of the impurities within the stone from Very, Very, Slightly Included VVS1 or VVS2 through Very Slightly Included (VS1 & VS2) to Slightly Included (SI1 & SI2) and then Included and industrial grade diamonds.