Diamond Grading Information

The cut, also called the diamond's "make," is extraordinarily important because it has the greatest single influence on the diamond's brilliance, or sparkle. And when it comes to diamonds, sparkle is what makes diamonds "a girl's best friend."

A poorly cut diamond isn't worth buying at any price.
Occasionally you may find other jewelers' stones are priced lower than Shane Co. diamonds of identical carat weight, color and clarity. That's because the diamonds at the other jewelers are cut too shallow or too deep – causing the light that enters them from above to leak out of the bottom and sides of the stone. As a result, these stones are visibly dull and dark and consequently, highly undesirable. Remember: it takes all four Cs to complete the picture and determine a diamond's value.

A diamond that doesn't sparkle isn't worth buying, no matter how low the price may be. So pay special attention to cut when evaluating diamonds and believe your eyes.

Shane Co. handpicks only diamonds with the most sparkle.
Judging a diamond’s sparkle by its lab grade alone is like judging a movie solely by its rating. A laboratory grade is only part of the story, because diamonds with the same grade can have very different amounts of sparkle, depending on how each diamond is cut and where the inclusions are located inside the diamond. When Shane Co. buys diamonds, our own buyers go directly to the diamond cutters around the world and examine groups of diamonds already sorted by grade. Then they handpick only the diamonds with the most sparkle from within each grade. Whatever diamond grade you choose, you will clearly see the difference in the way  Shane Co. diamonds sparkle.

Cut specifically addresses the number, placement, angling and shape of the facets to create a polished diamond. The facets function as prisms, capturing and reflecting light inside the diamond. The quality of a stone's cut is primarily determined by the height of the crown relative to the depth of the pavilion and the width of the table.

Crown	The part of the diamond above the girdle
Table	The large facet that caps the crown of a stone
Girdle	The outer edge of the diamond, usually the portion that is grasped by the setting. It is the dividing line between the crown and the pavilion.
Pavilion	The part of the diamond below the girdle.
Culet	The small facet parallel to the girdle, at the bottom of the stone.

An exacting talent
Of the four qualities that define a diamond's value, the cut is the only one determined by a human being. A skilled diamond cutter realizes the rough diamond's potential. He cuts and facets the crystal to reflect the maximum amount of light inside the stone and back through the top of the diamond. His objective is to produce a perfectly symmetrical stone whose right and left sides are mirror images of each other.

At the same time, he has to find the optimal balance between yielding the most diamond weight and creating the best proportioned cut. One reason why higher grades of cut are so much more costly is because more diamond was sacrificed to create them. That's also why a well proportioned one-carat diamond may be worth twice as much as a poorly proportioned larger diamond that lacks fire and brilliance.

In search of the "ideal"
For centuries, diamond cutting experts have pondered what combination of proportions creates the optimal balance of brilliance, scintillation and dispersion (the diamond's sparkle and fire).

The 58-facet model developed in 1919 by master gem cutter and mathematician Marcel Tolkowsky has provided a foundation for today's most widely accepted proportions. However, while Tolkowsky's model dictated precise proportions for table diameter, crown height, pavilion depth, crown angle and pavilion angle, many grading labs and diamond sellers today offer a more liberal interpretation. The market itself dictates a wider range of acceptable proportions.

In fact, the Gemological Institute of America (GIA), the world's leading gemological authority, actually advises against using the term "ideal" cut. Why? Because the GIA has demonstrated that literally thousands of variations on these proportions can maximize the different optical characteristics displayed by a diamond. As long as the diamond's proportions fall within the acceptable range of tolerances (and Shane Co. searches the world's markets for the finest cuts), you can be assured of buying a stone that is well made. Furthermore, you could view two stones with vastly different cut proportions, and be hard-pressed to determine which stone is more beautiful.

For appearance's sake
The way a stone is cut can affect its appearance in other ways. If the diamond has a deep cut, it actually looks smaller than another diamond of the same weight that is cut well. Likewise, a diamond that has a spread cut (cut shallow) will appear larger than another diamond of the same weight that is cut well. A diamond that is cut either too deep or too spread is typically undesirable.