Diamond Cut – The 4Cs of Diamonds

The 4Cs of DiamondsCut is the factor that creates a diamond’s fire, sparkle and brilliance.

The traditional cut of 58 facets in a standard round brilliant diamond, all precisely cut and defined, are as small as two millimeters in diameter. But without this level of precision, a diamond wouldn’t be as beautiful. The luster of a particular diamond depends more on cut than anything else.

Though extremely difficult to analyze or quantify, the cut of any diamond has three attributes: brilliance, which is the total light reflected from a diamond, fire, which is the dispersion of light into the colors of the spectrum, and scintillation, which causes the flashes of light, or sparkle, when a diamond is moved.

Understanding of the diamond cut begins with the shape of a diamond. The standard round brilliant is the shape used in most diamond jewelry. All other cuts are known as fancy shapes. The traditional fancy shapes include the marquise, pear, oval and emerald diamond cuts. Hearts, cushions, triangles and a variety of others are also gaining popularity in diamond jewelry.

As a value factor, though, the cut refers to a diamond’s proportions, symmetry and polish. For example, look at a side view of the standard round brilliant diamond . The major diamond components, from top to bottom, are the crown, girdle and pavilion. A round brilliant cut diamond has 57 or 58 facets, the 58th being a tiny flat facet at the bottom of the pavilion that’s known as the culet. The large, flat facet on the top of a diamond is the table. The proportions of a diamond refer to the relationships between table size, crown angle and pavilion depth. A wide range of proportion combinations are possible in diamonds, and these ultimately affect the stone’s interaction with light.

In early 2005, GIA unveiled the  diamond cut grading system for standard round brilliant diamonds in the D-to-Z color range. This system, the product of more than 15 years of intensive research and testing, assigns an overall diamond’s cut grade ranging from Excellent to Poor.

How does pavilion depth affect a diamond’s cut?

The distance from the bottom of the girdle to the diamond culet is the pavilion depth. A pavilion depth that’s too shallow or too deep will allow light to escape through the sides or the bottom of the diamond . A well-cut stone will direct more light through the crown.