Diamond Education

The 4 C’s – Carat Weight, Color, Clarity, and Cut


Originally measured with lots of carob seeds, the more standardized measures are a carat. A carat is equal to 200 milligrams, or about one fifth of a gram. This means there are 142 carats in an Avoirdupois ounce.

A carat is broken down further into 100 equal parts or points. A one-carat diamond would be 100 points, a half-carat diamond is 50 points, and quarter carat diamond is 25 points, etc.

A diamond is usually priced on a per carat basis, according to its size and quality. Where two diamonds have exactly the same carat weight, the one of better quality will command a higher price per carat. Because the rarity of diamonds increases with their size, so does their price per carat; a two-carat diamond will cost more than twice as much as a one-carat diamond of the same quality.


Most diamonds are transparently clear, or white, but with a tinge of body color that can be seen when one looks through the side of the diamond against a white background. Completely colorless, icy white diamonds are very rare, only a small percentage of all gem diamonds. Because of this rarity, diamonds command premium prices.

Not as rare are diamonds with a tinge of color so faint that it is discernible only to the eye of an expert. Nevertheless, such diamonds command higher prices than those in which the body color is easily seen. For some reason, diamonds with a tinge of color seem to have more fire, a warmer beauty, than icy white stones.

Although white diamonds are most common, there are diamonds in all colors of the spectrum.

Though most are yellow and brown, they occur in shades of pink, orange, green and blue. These are called fancies, and are valued for their rarity.


Because Nature is rarely perfect, most diamonds show imperfections, or characteristics of crystallization. These are called inclusions because they are within the stone tiny bubbles, specks of uncrystallized carbon, hairlines or feathers. Such inclusions are not structural weaknesses. But they affect the clarity of the diamond to the degree that they interfere with the passage of light through the stone.

In some diamonds, there are inclusions visible to the naked eye. The brilliance and fire of these stones is less than that of diamonds whose inclusions are not visible, and so they have a lesser degree of clarity.

A flawless diamond has “top clarity”. By Federal Trade Commission standards, a flawless diamond is one in which no inclusions are visible to a trained eye using a 10-power magnification in optimum light conditions.

A diamond does not have to be flawless to be beautiful. In a sense, the inclusions in a diamond are its fingerprints, because the number, type, and location of inclusions in one diamond are rarely duplicated in another.

Diamond Cutting

The beauty of a gem quality diamond depends on the way it handles light. Diamond cutting unlocks this beauty.

The ancient Indian lapidaries learned that rubbing another diamond against them could polish the surfaces of a diamond. In the 15th century important discoveries were made which resulted in even brighter stones through the grinding of additional facets or planes.

In 1919 Marcel Tolkowsky, a physicist, developed the relationship of facet angles that is still considered ideal for modern diamond cutting today.

Antwerp and Israel (around the area of Tel Aviv) are the largest diamond cutting centers in the world. Other important centers are Amsterdam, United States, India, West Germany, and South Africa.

The planner of cutting the rough material has to be conscious of two factors. Under normal circumstances, a rough diamond loses more than half its weight in the cutting process; so the planner has to determine the optimum shape that will retain as much diamond weight as possible.

Most diamonds contain natural imperfections, or inclusions; so the planner has to position the finished shape and direct the cutting so that as many inclusions as possible can be ground away, and the remaining inclusions will offer little interference with the passage of light through the stone.

It takes hours to cut through even a small diamond. However, one sawyer can handle a battery of saws, checking each stone at intervals to ensure that it is being sawed correctly. The deviation of even the width of a hair can affect the finished gem.

Cutting is a long, exacting, and expensive process. Cutters are skilled craftsmen who must use the judgment gained by many long years of experience to bring out the full beauty of a diamond.