Diamond Carat Weight
The weight of a diamond is expressed in carats (ct). One carat is equal to 200 milligrams, or 0.2 grams.
In pricing, there's an enormous difference between one carat total weight (1 ct. TW) versus the weight of one stone (1 ct.). Knowing the "per carat cost" will help you understand the actual diamond price.
For example, a one carat diamond is much more valuable and much more expensive than a grouping of several diamonds that combine to add up to one carat in total weight.
A poorly cut diamond, one cut too deeply or too shallow, will allow light to escape through the opposite side or through the bottom of the stone before it can reflect light back to the surface.
The cut is the outline shape of the diamond and the quality of the diamond's proportions. It is an important factor in determining the fire and brilliance of a diamond. When a diamond is well proportioned, light is reflected from one facet to another which provides the diamond with fire and brilliance.
In shallow cut diamond, light is lost out the sides causing the diamond to lose brilliance. A deep cut diamond, light escapes out the bottom causing the diamond to appear dark and dull. As a result, poorly cut stones will be relatively less brilliant and attractive than well cut diamonds.
Most diamonds appear colorless but actually have slight tones of yellow or brown. The closer the stone comes to colorless, the more valuable it is. Diamonds are graded on a color scale ranging from D (colorless) to Z (heavily tinted.) Only a highly skilled professional will detect any color in E or F stones, and the color in diamonds rated up to J will be virtually invisible when set in a ring or other jewelry
It is very common for diamonds to be formed with slight imperfections. These are known as "inclusions" and can come in many forms, including tiny white points, dark dots, or feathery cracks. The fewer inclusions, the more the stone is worth.
FL Flawless: Free from all Inclusions with 10x magnifications
IF Internally Flawless: No Inclusions visible at 10x. Insignificant surface blemishes.
VVS-2 Very Very Slight Inclusion. Eye Clean.
VS-2Very Slight Inclusion
SI-3 Slight Inclusions. Eye clean face up
I-2 Inclusions. Visible to the naked eye.