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| The 4 C's Many tons of ore must be mined to produce a 1-carat diamond. This combined with the fact that diamonds are unique in their amazing ability to reflect light, has made them the most valuable of all gems. Furthermore, no two diamonds are the same - each one has its unique beauty. When buying a diamond, you should consider the following criteria, commonly known as the 4C’s: Carat - Clarity - Color - Cut CERTIFICATION Certification of diamonds of exceptional quality is common practice within the diamond industry. At REX we mainly certify our diamonds at the Diamond High Council (HRD: www.hrd.be) of Antwerp or at the Gemological Institute of America (GIA: www.gia.org). 1. CARAT A diamond's weight is measured in carats. Derived from the Arabic word "quirat", a carat is roughly equal to 0.2 grams. A carat is further subdivided in 100 points. The carat weight is easily measured with an electronic balance. If the diamond is polished in the shape of a round brilliant, its weight can be estimated quite accurately merely by measuring the diameter of the stone. The following chart shows the width of diamonds of specific weights:
2. CLARITY Clarity grades are used for polished diamonds to describe in a standardized manner whether the diamond has any flaws or imperfections that would affect its faceted appearance. They are universally accepted by all gem laboratories. Almost all natural diamond crystals contain characteristics that can affect their appearance when polished. Such characteristics typically consist of fractures or inclusions or foreign material that may vary in terms of size, visibility, location and number.
For fine jewellery collections it is better to avoid inclusions that are visible to the naked eye. Therefore, we at REXdiamonds will only use diamonds of at least VS2 clarity grade to create the finest jewellery. Diamonds over one carat are always accompanied by a certificate. 3. COLOR The color of a diamond is assessed in terms of a color scale that is accepted worldwide. Only few diamonds, called fancies, are naturally colored diamonds and may be yellow, green, pink, blue, black or red. Most diamonds are slightly tinted, varying from colorless (D) to light-yellow, green, pale-brown or gray. In the 1950's, the Gemological Institute of America (GIA) introduced a simple grading system for colorless-to-light-yellow diamonds: the D to Z color grading.
The color of diamonds can be enhanced by radiation. REX offers only untreated diamonds. 4. CUT This is perhaps the most important of all the 4 C's, and among the hardest to judge, as there is no standard grading system for cutting styles. All other factors being equal, a poorly cut diamond can be worth less than half the value of a well "made" diamond. Diamond cutters are skilled to retain the maximum weight from the rough stones. A well-cut round diamond weighs only about 40% or less of the original weight of rough diamond the cutter started with. In order to maximize the diamond's brilliance it must be cut in a geometrically precise manner. Symmetry, polish, and faceting are the most noticeable features of cut but also important are percentages for depth, height and angles. To bring out the most return of lights (its " brilliance") and reflected color flashes (its "dispersion" or "fire"), flat polished surfaces (facets) are created on the diamond crystal. Light should enter and exit a diamond through the top facets to maximize its brilliance. A cut that is too shallow or too deep reflects it through the bottom facets, and lets the light "leak" out of the bottom or side of the gem. The shape of a polished diamond is ascertained by viewing its outline from above. Below you will find the most usual cutting styles for diamonds.
If you would like to obtain more general information about diamonds, may we suggest you visit following sites: • www.rexmining.com • www.amnh.org/exhibitions/diamonds |
