The 4 C's
A diamond is judged by four distinct factors that combine in a number of ways to arrive at its value. These factors are called the four C's.
The size is what we first notice in a diamond, but definitely is not the most important feature. Carat is the weight measurement of a diamond, approximately 0.2 gram. The more a diamond weighs the larger it appears physically. Larger diamonds are more rare therefore more expensive.
The internal characteristics of a diamond define its clarity. These characteristics are all natural and usually invisible to the naked eye. When examining a diamond with 10X magnification these characteristics appear as tiny feathers, clouds, or crystals. The clarity grade is arrived by considering the size, number and location of these identifying characteristics.
Diamonds appear to be colorless, but it is sometimes surprising to learn that they actually have slight tones of yellow or brown. The color grading scale ranges from D, or colorless, all the way to Z. Colorless diamonds are rarer and therefore more valuable.
The proportions to which a diamond is cut dramatically influences the brilliance, fire and sparkle. If a diamond is cut too deep or too shallow it will loose its brilliance because it is not reflecting the light to its optimum potential.
A diamond is ideal cut when its proportions fall into a precise range of measurements, as shown in the diagram below. These measurements give the diamond optimum brilliance, fire and sparkle.
Hearts and Arrows
This a pattern that can be seen when viewed through a hearts and arrows scope. This pattern occurs in a ideal cut diamond that has near perfect symmetry.