Cut is the shape and proportion of the stone. When a stone is cut to excellent proportions, light is reflected from facet to facet, then dispersed through the top. Symmetry and Polish affect the scintillation. The better the cut, the greater the sparkle, brilliance and fire of the stone. Ideal cut diamonds are very rare. The small differences can only be measured in a laboratory as the eye cannot see them.
Optimal color in diamonds is actually colorless. Though most diamonds appear colorless, they have subtle shade differences that range from colorless to yellow and brown. Diamonds are graded on a color scale that ranges from D to Z. Diamonds with no hint of color at all are extremely rare and are therefore most valuable.
Almost all diamonds contain a combination of internal and external characteristics called inclusions and blemishes. Normally, they are too minute to be visible without powerful magnification. Industry standards are 10X magnification. Some are even so small they require great skill and time to locate. The number, type, location, durability, visibility and color of inclusions determine a diamond’s clarity and may influence its value.
The weight or size of a diamond is measured in carats. A one carat stone is equal in weight to one hundred smaller units called “points”. For example, a fifty-point diamond is factored in the same as half carat. Carat weight is the most obvious factor in determining a diamond’s value, depending on the quality of its cut, clarity, and color. In determining whether to select a smaller diamond of better overall quality or a larger diamond which might sacrifice a marginal degree of grading, please consider when worn in jewelry, prongs can cover some inclusions.