A diamond is the hardest naturally occurring substance known to man and when combined with the brilliant fire of the cut and polished finished product, has made diamonds one of the most valuable gemstones in the world.
Diamonds in all of their glory are pure carbon, just the same way lead pencils used to made from graphite which is also pure carbon, it is the way the carbon atoms are arranged which makes the difference between cheap, dull graphite or brilliant, fiery diamond. Diamonds are formed at great pressure and temperature inside the earth; at least 50 miles below the surface where the pressure is so intense that the carbon atoms are compressed together into an extremely packed formation and which gives diamond its strength. Diamonds are brought to the surface as a result of the natural, geological processes of the earth or more usually, are sought in some of the deepest mines in the world.
Brazil and India used to be the principal sources of diamonds with their gemstones being sourced from rivers and gravel deposits which had come to or close to the surface naturally. In 1870, Kimberlite rock was discovered to be richly laden with diamonds in South Africa and now, huge masses of rock are mined and processed to extract the diamonds it contains. To put it into some perspective, for one carat of polished diamond over 250 tons of Kimberlite ore must be mined and processed - now you understand why diamonds are so expensive!
Once extracted from the ore, the rough diamonds must be sorted and processed further. Processing includes cutting and polishing as at this stage, the diamonds resemble pebbles you would encounter on a beach and are nondescript in appearance. Cutting and polishing the rough diamond brings out the internal fire and beauty of the diamond, however, it is how a diamond is cut which determines the level of light which enters the stone and is internally reflected before exiting the diamond - this level of internal reflection is what adds to the sparkle and brilliance of the stone so cutting a diamond properly is essential or it will appear dull.
After being cut and polished, diamonds are then graded according to a system know as the "Four C's". The Four C's are - Carat (or weight), Cut, Clarity and Color. A carat is equivalent to 0.2 grams but you must take care not to confuse diamond size with weight - a carat is a measure of weight and not size; a smaller looking diamond may very well be a larger weight of a much larger diamond simply because of composition and the way it has been cut. The cut, as we have seen, determines how much light enters and internally reflected within a diamond thus bringing out the fire or brilliance - too shallow a cut, where the diamond is not deep enough to allow the internal light reflection, will mean the diamond looks dull instead of fiery - this is a poor cut and underlines why diamond cutting is a highly skilled art.
Clarity refers to how clear and flaw-free the diamond is; diamonds will contain flaws which may be foreign matter enclosed within the diamond when it was forming in the earth or bubbles of gas and even internal faults where the carbon atoms have not uniformly bonded together. The presence of flaws affects the visual appearance of the diamond but also influences how light will travel and internally reflect within it; for these reasons, a flawless diamond is considerably more valuable than one with flaws.
Finally, color - diamonds can come with a yellowish tinge or at the other end of the scale have no color whatsoever - no color means a brighter and fiery brilliance whereas the yellowish tinge will dampen the brilliance of the diamond. The less color a diamond has the more valuable it is and the more you are going to pay for it.
By Lawrence Reaves