Shapiro Diamonds believes Diamond Cut is the most important of the 4Cs to consider. Cut effects the brilliance of a stone and can dramatically impact the “fire and brilliance” a stone has. Consider cut above all else.

“Cut” refers to the angles and proportions of a diamond. Based on scientific formulas, a well-cut diamond will internally reflect light from one mirror-like facet to another and disperse and reflect it through the top of the stone. This results in a display of brilliance and fire, thereby placing well-cut diamonds higher on the Diamond Quality Pyramid than deep or shallow-cut diamonds.

What makes a diamond stand out beyond any other precious gemstone is its fire and brilliance. While nature determines the color and clarity of a stone, diamond cut is dependent solely upon the skill of the cutter.

The cut of a diamond is what determines how the light that enters the diamond is reflected and therefore how much fire and brilliance the diamond will exude. A diamond that is cut too shallow with respect to its width will allow too much light to pass straight through the diamond, leaving little light to reflect. Such a diamond will appear dull and lacking in brilliance. Conversely, a diamond cut too deeply will allow light to escape from the sides of the diamond, also appearing dull.

Shapiro Diamonds Carries Only Ideal and Premium Cut Diamonds.

Shallow Cut: Light is lost out the sides, causing the diamond to lose fire and brilliance.

Deep Cut: Light goes straight through the diamond, causing the diamond to appear dark and dull.

Ideal Cut: This is a very rare cut, that reflects nearly all light that enters the diamond and creates the maximum fire and brilliance. Represents roughly the top 3% of diamond quality based on cut.

Premium Cut: Reflects almost as much light as the Ideal Cut, but for a lower price.

Good Cut: Reflects most light that enters the diamond, but not as must as a Premium Cut diamond. This is less expensive than the Premium Cut. Represents roughly the top 25% of diamond quality based on cut.

Fair Cut: These still are a quality diamond, but a Fair Cut diamond will not be as brilliant as a good cut. Represents roughly the top 35% of diamond quality based on cut.

Poor Cut: These diamonds are deep and narrow or shallow and wide and tend to lose most of the light out the sides and bottom. This includes all diamonds that do not meet the proportion standards of a fair cut.

The depth and table measurements, which are used to determine how good the cut is, are given in percentages of the girdle (the widest part of the diamond). So, if a diamond’s girdle measures 10 millimeters, the table measures 5.6 mm, and the total depth measurement is 6.25 mm, it would have a table of 56% and a depth of 62.5%. What percentages will yield an ideal cut vary from shape to shape. The table below gives percentage ranges of a good cut for different shaped diamonds.

In order to cut a stone to ideal proportions, much of the rough diamond is sacrificed, leaving a stone with a smaller carat weight. Diamond cutters sometimes sacrifice ideal proportions to end up with a larger, more profitable stone. Industry standard valuation of diamonds (Rapaport) does not take into account a diamond’s proportions, thus a larger diamond with fair proportions will be worth more than the smaller diamond with good proportions to a diamond cutter (color and clarity being equal). Consequently, ideal cut stones are very rare and hard for wholesalers and retailers to find, and as the consumer, you will see that retail jewelry stores price accordingly.

It is important not to confuse diamond shape with diamond cut. Cut refers to the symmetry, proportioning and polish of a diamond. Shape refers to the outer edges of the diamond and the outer form in which it takes – square, round, rectangular, pear-shape, etc.