 |
The traditional 58 facets in a round brilliant diamond, each precisely cut and
defined, are as small as two millimeters in diameter. But without this
precision, a diamond wouldn’t be nearly as beautiful. The allure 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 (the total light reflected from a diamond), fire
(the dispersion of light into the colors of the spectrum), and scintillation
(the flashes of light, or sparkle, when a diamond is moved).
An understanding of diamond cut begins with the shape of a diamond. The standard
round brilliant is the shape used in most diamond jewelry. All others are known
as fancy shapes. Traditional fancy shapes include the marquise, pear, oval and
emerald cuts. Hearts, cushions, triangles and a variety of others are also
gaining popularity in diamond jewelry.
As a value factor, though, cut refers to a diamond’s proportions, symmetry and
polish. For example, look at a side view of the standard round brilliant. The
major 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 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, and these ultimately affect the stone’s
interaction with light.
In early 2005, GIA unveiled a diamond cut grading system for
standard round brilliants 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
cut grade ranging from Excellent to Poor.
|