Diamond are the King of gems! A diamond's rarity and hardness cannot alone explain it's position as the king of gems. Desirability as a gem requires beauty as well as rarity and durability.
To understand the visual appeal of diamonds you need to consider the famous 4 C's - Carat weight, Colour, Clarity, Cut.
Carat weight - Diamonds are weighed in metric carats (usually abbreviated to ct.) and just as a pound is divided in to 100pennies, a carat is divided into 100 points ie a diamond of 50 points is 0.50ct. or half a carat.
In theory a brilliant cut diamond for example, will be cut to certain standard proportions, so by measuring the diameter of the stone at the girdle, you are able to arrive at an estimated weight. If you are able to measure the depth of the stone (ie if it is a loose stone) then a more accurate weight can reached.
Colour - The ideal colour for a diamond is an absolute lack of colour ( D ), ranging through to slightly tinted white (I and J) and down to tinted and fancy coloured diamonds (M- Z).
Clarity - Because diamonds are formed deep within the earth, under extreme heat and pressure, they often contain unique birthmarks, either internally (inclusions) or externally (blemishes). Diamond clarity refers to the absence of these inclusions and blemishes. Diamonds without these marks are rare and rarity increases value. Diamonds are assigned a clarity grade that ranges from Flawless (FL) to diamonds with obvious inclusions (PK)
Cut - This is the factor that fuels a diamonds fire, sparkle and brilliance. Cut refers firstly to the shape of the diamond, the most desirable being the round brilliant cut diamond and others including the princess cut diamond (square), oval, emerald and marquise cuts. The cut also refers to a diamonds proportions, symmetry and polish, the basis of which is specific optical calculations aiming at maximising the beauty of each stone.
There is now a 5th C to consider!
Today in the jewellery industry there is much talk of diamond grading and diamond certificates. Many diamonds of more than a quarter of a carat or so in weight are now sold with a laboratory grading report - a professional report accurately describing the weight, colour, clarity and other measurable characteristics of the stone. We typically stock GIA certificated stones - these reports are from the Gemmological Institute of America, widely regarded as the World's most trusted name in diamond grading. Their tagline is 'The difference between wondering and knowing' - we think that speaks for itself!