Education: Diamonds: The Four C’s



Ancient gem traders used carob seeds to balance their scales when buying stones. From this we get the modern word “carat” which is the standard unit of gemstone weight. The carat is divided into 100 “points” (just as a dollar is divided into 100 cents). For example a diamond weighing exactly one-half carat (.50 ct.) can be described as weighing 50 points. A diamond that weighs 105 points (1.05 ct.) weighs just over 1 carat and so on. Two diamonds of the exact same weight may be vastly different in value depending on the other C’s.


The vast majority of diamonds that the earth gives up are either brown, gray, or yellow, and are not suitable for use in fine jewelry. However, a small percentage exhibit little or no perceptible color (known as “white” or “near-white”). These are the diamonds most desired as treasured gems. Most gem quality diamonds appear colorless, but do have a slight, barely visible tint of color when viewed unmounted under special lighting. The color grade is determined by how close to colorless the diamond is. A whiter (or, more nearly colorless) diamond is rarer and therefore more highly valued.


Nature rarely creates perfection, and diamonds are no exception to this rule. Most gem quality diamonds contain minor birthmarks, called inclusions, attesting to the incredibly violent environment in which they were formed. Most inclusions are difficult, if not impossible, to see without the aid of a microscope and don’t usually affect the beauty of a diamond. But they do identify the diamond as natural (“real”), and distinguish it from any other diamond in the world. The clarity grade is determined by the ease with which these natural characteristics can be seen under a microscope. A diamond with smaller, more difficult-to-spot inclusions is rarer and thus more valuable.


Cut refers not only to the overall shape of a diamond – round, marquise, princess, etc.- but also, and more importantly, the accuracy and precision of the cutting. The cutting quality (or “make”) determines the overall brilliance and beauty of a diamond. A round, brilliant-cut diamond, for example, has 58 little individually cut and polished planes (facets) that must be in exact alignment and proportion to each other in order to achieve maximum brilliance and fire. A well cut diamond dances in the light, a poorly cut stone (in industry jargon) is “sleepy”. Naturally, a well cut diamond is more valuable and desired.