DIAMOND EDUCATION

Diamond Cut – The Essential Characteristic

Cut refers to a diamond's proportion and the quality of its polish and symmetry.  When the cut is of a high quality, a diamond can exude brilliance, fire, and scintillation.  For this reason, the diamond cut is often considered the most important characteristic of a diamond.

Five Major Parts Comprise Every Diamond

Why It Means So Much

Poor cut can limit the amount of light that enters a diamond.  Just as important, it can allow light to escape out of the bottom of a stone.  Naturally then, well-cut stones are more valuable than diamonds of poor cut.  Cut is the only characteristic that depends on the human touch, and says much about the skill of the diamond cutter.  Even if color and clarity are very high, a poorly cut diamond will not exude brilliance. 

Light and Its Effect on a Diamond

(A) Reflection A ray of light hits the diamond's surface. Some of the light enters, and part of the light reflects back. The immediate reflection is the light given off by the crown angles.

(B) Refraction The remaining light enters the diamond and reflects toward the center of the diamond. The light that bounces off the internal wall of the diamond is the refraction.

(C) Dispersion The ray of light then shoots to the surface through the top of the diamond. A color spectrum is visible when light exits the diamond.

It's All About Angle, Depth and Surface

A diamond's pavilion angle and depth must be correct to capture light and throw it back to the viewer. A pavilion angle that is too shallow or too deep allows light to escape. The crown of a diamond is equally important. It is both the entry and exit point for light coming in and out of the diamond.

Symmetry
When the facets of a diamond are well balanced and aligned, the stone has symmetry, which is critical to creating optimal brilliance and scintillation. Errors in symmetry include facets that are not properly aligned, improperly shaped facets, or an off-center table.

Polish
After a diamond is cut, each facet must be polished. The process can leave surface scratches or marks, which are like streaks left behind after a car is waxed. If a diamond has no scratches or very minor ones, the polish is of a high degree. Scratches, lines, a burn mark created by excessive heat, or a rough girdle could downgrade the polish rating of a diamond.

In the world's diamond markets, to buyers in the know, make refers to a diamond's shape and the quality of its cut and finish. Every diamond at Brilliance is individually graded on a make scale based on four factors; Finish, Proportions, Light Performance, and Appearance.

Ideal Cut Diamonds

Round
Creating an ideal-cut diamond depends on three interrelated factors: table size, crown angle, and pavilion depth. The cutter needs to follow "blueprints" to ensure that these elements are ideal in proportion to one another. However, diamonds with proportions outside these standards can still show brilliance. Likewise, correct proportions do not necessarily result in a diamond of the highest-quality make.

Today, modern machinery is used to measure the make and light-throwing capabilities of diamonds. Learn about the standards each diamond laboratory uses to evaluate ideal cut.

Under a special viewer, an ideal cut diamond
shows hearts from the pavilion and arrows from the crown.

Fancy Shapes
There are no ideal-proportion standards for fancy-shape diamonds as there are for round-cuts. It is the diamond cutter's personal preference that determines the way each fancy shape is cut. Length-to-width ratio is a matter of individual taste, for example. Some cutters like elongated stones; others prefer wider shapes. No matter how good the cut, fancy-shape diamonds are never as brilliant as round-cut stones. That's because, scientifically, the facets and angles of the round-cut are ideal for refracting light back to the viewer. Bear in mind these factors when shopping for a fancy-shape diamond:

• Degree of brilliance. High-make diamonds are fiery with great light dispersion. A fancy-shape diamond should dance in the light, and light should not leak from the stone's pavilions.
• Symmetry. If you could split a diamond in half, the halves should be symmetrical. Length-to-width ratio is unimportant if the shape appeals to you.
• Bow tie effect. Some fancy-shape diamonds have what is known as a bow tie, two black triangles that appear to connect in the middle of a diamond. Although bow ties are normal in some fancy shapes, a bow tie that is too big detracts a diamond's beauty.