What are the 4 C’s
Cut quality is the factor that fuels a diamond’s fire, sparkle and brilliance. The allure and beauty of a particular diamond depends more on cut quality than anything else.
The GIA Diamond Cut Grading System for standard round brilliants in the D-to-Z color range is based on the assessment of seven components. The first three — brightness (the total light reflected from a diamond), fire (the dispersion of light into the colors of the spectrum), and scintillation (the pattern of light and dark areas and the flashes of light, or sparkle, when a diamond is moved) — are appearance-based aspects. The remaining four — weight ratio, durability, polish, and symmetry — are related to a diamond’s design and craftsmanship.
In GIA’s system, each component is assessed individually, taking into account the relative importance of that component in the overall cut quality of the diamond. Each cut grade, based on a relative scale from Excellent to Poor, represents a range of proportion sets and face-up appearances. There are many different proportion sets that produce attractive diamonds.
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. It is important to note that a wide range of proportion combinations are possible, and these ultimately affect the stone’s interaction with light and how attractive the diamond is to the person viewing it.
The diamond, which has an even pattern of bright and dark areas, scores in the top category for all grade-setting determinants.
Although its proportions are different from the diamond in the first example, this diamond also has an even pattern of bright and dark areas and scores in the top category for all grade-setting determinants.
This diamond also scores in the top category for all grade-setting determinants.
This diamond’s grade is determined by brightness, scintillation, and polish. Although no individual proportions would necessarily cause its brightness or scintillation to perform poorly, the combination of this particular set of proportions leads to increased darkness in the pavilion mains.
This diamond’s grade is determined by its fire, scintillation, and weight ratio. It has a “splintery” pattern, most likely caused by a higher crown height with a somewhat steeper crown angle, accompanied by a long lower-girdle facets.
This diamond’s grade is determined by its brightness, scintillation, and finish. There is a slight darkening within the table and along the upper-girdle facets.
This diamond’s grade is limited by its scintillation. In this case, the somewhat shallow pavilion angle produces dark pavilion mains.
This diamond’s grade is determined by its fire, scintillation, and weight ratio. A somewhat steep crown angle, combined with a slightly steep pavilion and this total depth, leads to a diamond that displays a slightly dark ring within the table edge, as well as somewhat dark upper-girdle facets.
This diamond’s grade is limited by its scintillation. The shallow crown angle and low crown height lead to a face-up appearance with a lack of contrast in its pattern and localized darkness (especially in the table area).
This diamond’s grade is limited by its scintillation. The combination of a shallow crown angle and a somewhat shallow pavilion angle leads to a face-up appearance with a lack of contrast and general darkness.
This diamond’s grade is determined by its fire, scintillation, and weight ratio. A slightly steep crown angle, combined with a steep pavilion angle and large total depth, causes this diamond to display general darkness in the table area and a very dark upper-girdle area.
This diamond’s grade is limited by its brightness and scintillation. The large table and a somewhat shallow crown height, with this pavilion angle, cause a general darkness in this diamond, along with a slight fisheye that becomes more evident when the diamond is tilted.
This diamond’s grade is limited by its weight ratio. Although most of the proportions for this diamond are fairly standard, the extremely thick girdle greatly increases the total depth. Therefore, this diamond’s diameter is much smaller than its carat weight would indicate.
This diamond’s grade is limited by its fire and scintillation. This slightly steep crown angle, very steep pavilion angle, and large total depth all cause this diamond to have a very dark table area, along with a very dark upper-girdle areas.
This diamond’s grade is also limited by its weight ratio. The somewhat steep crown angle, slightly steep pavilion angle, and very thick girdle greatly increase the total depth. Therefore, this diamond’s diameter is much smaller than its carat weight would indicate.
While it is important to consider many components when assessing the overall cut appearance and quality of round brilliant diamonds, an individual’s preferences also play a role. Because each cut grade represents a wide range of proportion sets, individuals have the freedom to choose which particular appearance they prefer within the grade range.
The diamond industry as well as the public can use cut along with color, clarity, and carat weight to help them make more informed decisions when assessing and purchasing round brilliant diamonds.
CUT VS. SHAPE
People often use the words cut and shape interchangeably. They think of cut as the shape or outline of the diamond, rather than the arrangement of facets needed to create an attractive face-up appearance.
Round is the shape used in most diamond jewelry. All other outlines are known as fancy shapes. Examples of traditional fancy shapes include the marquise, pear and oval. Hearts, triangles and a variety of others are also gaining popularity in diamond jewellery.