We measure diamonds using the term carat; this term comes from the word carob. A carob is a bean grown in the Mediterranean, if the stone weight was the same as one carob bean then it was a 1 carob (or carat) diamond. Over time, this weight, which was none to precise, was standardized to 0.2 grams or 200 milligrams. In the far east where no such tree grew a diamond was measured in grains of rice if a diamond is referred to as 4 grains this would equate to what we now know as a one caret stone.
When shopping for diamond jewellery that is already set, it will be marked as CTW or carat total weight. This does not tell you the individual weights of the mounted stones. You will need to pick the brains of the jeweller to find out the carat weight of the largest stone in the setting, this will help you to put into context exactly what you are buying.How to pick a diamondWhen selecting a diamond there are four things you need to understand, Known in the trade as the four C's. The criteria are colour, cut, clarity and lastly carat. The colour is a reference to the inclusion or absence of colour in white diamonds. The lack of colour is a positive aspect this allows for maximum light to pass through making it sparkle brightly. The cut is a very important aspect it can make a diamond sparkle with all is glory or it can dull down its beauty. It can also have an impact on the durability of the stone as well, any cutting faults can make a diamond prone to breakage. A thin cut stone can also leak light from the rear making the stone loose some of its brilliance.The number and size of inner flaws or "inclusions" govern the clarity of a diamond. These inner flaws were formed when the diamond was being made in the earth. To be considered a flawless diamond there must be no surface as well as no inner flaws visible when viewed by a skilled gem stone grader using a 10-x magnifying eye glass The caret, as we discussed earlier is the measure of weight and one carat equals 0.2 grams As you can see there is a lot more to diamonds then just a pretty stone, they are the rarest and most beautiful of gemstones. We as a people have put enormous value in this naturally forming stone. These stones that were formed deep in the earth billions of years ago and transported by molten rock to the surface have a hold on us that seems unbreakable. Men have died and fortunes have been made by the pursuit of this wonderfully beautiful stone.