“Measure twice and cut once” is the rule that works for many occasions including diamonds. Even though diamonds are always associated with brilliance and shine the way they look like that depends on how they are cut. Only in hands of a skillful master a dull raw stone turns into a radiant gem. Before we’ve focused on what diamond clarity to choose and what is the best setting for a diamond ring, but today we’ll draw your attention to a diamond cut.
A good diamond cut has many characteristics:
Diamond Width and Depth
The proportions of width and depth have a large impact on diamond brilliance, the reflection of white light that we see when we look at a diamond. Refer to the graphic on this page as you read the following descriptions.
Light traveling through a shallow cut diamond is lost out of the bottom of the stone and does not back into sight. The lack of light play makes shallow cut diamonds appear lifeless.
Light traveling through a diamond that’s cut too deep escapes out the sides, darkening all or portions of the stone.
Light traveling through an ideal cut diamond bounces back out the top of the stone, bringing its brilliance into view.
The graphic illustrates extremes. As with other diamond characteristics, there are are in-betweens for cut quality.
Symmetry is a term that refers to the alignment of a diamond’s facets, its flat and polished surfaces. The facets should be cut to achieve the best play of light.
You’ve seen diamonds flash when you move them in the light–that effect is called scintillation, and it occurs when light bounces among the facets. Light doesn’t reflect as it should if facets are misaligned, diminishing the fireworks display.
Diamonds graded Fair and Poor for symmetry usually have facets that are misaligned enough to affect the play of light.
The surface of the facets should be smooth and polished so that light can pass through them.
Common Problems with Diamond Cuts
- A broken or chipped culet.
A culet that’s missing or one that’s off center.
Misaligned or extra facets.
- A girdle that is too thick, creating poor proportions, or too thin, making it easier to damage.
A fringed girdle, with tiny cracks going into the diamond.
- A table that slopes to one side.
Always buy diamonds from a reputable jeweler and ask questions about diamond characteristics. Inspect as many diamonds as possible so that you can make good comparisons.
This article is taken from http://jewelry.about.com/cs/thefourcs/a/diamond_cut.htm