The value of a diamond is primarily determined based on the combination of factors that are sometimes also referred to as value factors. Diamond professionals use a set of four value factors to approximate the quality of a gem. These four factors are popularly called as the four C’s – Cut, Clarity, Color and Carat.
The cut determines the fire and brilliance of a diamond. ‘Cut’ is many times confused with the ‘shape’. Shape is the outward appearance of a gem, the outline of its perimeter, while the cut refers to a stone’s proportionality and finish. The way a diamond is cut, also affects its color and clarity.
A diamond is basically divided into three parts – crown, girdle and pavilion. Crown is the top portion of the stone. Girdle is the narrow strip between the crown and the pavilion and is measured by its thickness. Pavilion is the lower portion below the girdle. All these crown, pavilion and sometimes even girdle have flat polished surfaces that are called the facets. Some diamonds have a small facet at the bottom, which is called the culet.
Cut affects Brilliance
Brilliance is the white light reflecting ability of a diamond from its surface and inside the crystal. How well a stone is cut will determine how much brilliance and fire the stone exhibits. A well cut stone will reflect most of the light that enters its surface through the top.
The most popular shapes of diamonds are
Round Brilliant cut – The modern round brilliant cut is the one of the most popular cuts for diamonds and has 58 facets. This cut is also referred to as full cut, and is known to maximize the fire and brilliance of diamonds.
Emerald cut – As is evident from the name, this cut was originally devised for emeralds, but then later started being used for diamonds as well. These cuts are rectangular step cut with rounded corners, loved for the elegance and subtlety that they bestow on the gem.
Cushion cut – Also referred to as Pillow cut, cushion cut has been around for more than a century and is much admired for its unconventional appeal. It has squarish shape rounded on the edges.
Asscher cut – This cut was first developed by the Asscher Brothers in the year 1902. It is a stepped square cut that GIA describes as ‘Modified Square Emerald Cut’. The classic Asscher cut has 72 facets and it gained much popularity in the Art Deco jewelry.
Princess cut – Also referred to as Quadrillion, it is known to display the same brilliance and fire as a round brilliant cut diamond. One should take care that the setting should protect the four corners in a princess cut diamond as they tend to chip.
Radiant cut – Radiant cut has the shape of emerald cut and the brilliance of round diamond. The ideal radiant cut has 70 facets and is often used for center pieces.
Oval cut – Developed by Lazar Kaplan in the 1960’s, these are narrower and longer variation of round diamond. The ideal oval cut has 56 facets, and given the same brilliance as round diamond, it costs much lesser.
Pear shaped – They are also referred to as ‘tear drop’ diamond given their shape. An ideal pear shaped diamond has 58 facets.
Marquise – A marquise diamond is a stretched oval with pointed ends. History tells that Louis XIV dedicated this to his beloved Marquise de Pompadour. A typical marquise would have 56 facets.
Trillion – Triangular brilliant, trilliant and trillion are standard terms to refer to a triangular cut diamond. It is a popular shape for center stone and side stones. Trillion has its corners rounded and its variety of facets gives the stone its sparkling brilliance.
Heart shaped - A heart shaped diamond is basically a pear shaped diamond with a cleft at the top. These diamonds are much loved for their romantic shape they make exquisite center stones.
Clarity
Clarity is another very important factor that affects the quality of a diamond. The clarity of a gemstone is primarily characterized by the presence of inclusions and blemishes.
Inclusions are inside the crystal structure of a diamond. It could be in form of air bubbles, cracks or some other non diamond mineral that become a part of diamond. Inclusions are a part of diamond since its formation and they give each diamond its unique identity. Now with the evolution of technology in the field of gems and with treatments such as laser treatment and fracture filling it is possible to enhance its clarity.
Blemishes are the flaws on the surface of a diamond. They are the scratches and nicks on a gem’s surface and it is the job of the cutter to minimize these blemishes from a diamond’s body.
Inclusions are not always bad. They may have very little or no effect of the brilliance and fire of a diamond. They give diamond its unique fingerprints and help gemologists to separate diamond from simulated ones.
Flawless diamonds are very rare. Many inclusions and blemishes may not be visible to the naked eye and are viewed with the help of standard 10X magnifying loupe.
GIA categorizes diamonds based on their clarity as
Category |
Grade |
Description |
Flawless |
FL |
No internal or external flaws. Very rare and precious. |
Internally Flawless |
IF |
No internal flaws. Some minute external flaws. Again very rare and precious. |
Very Very Slightly Included |
VVS1, VVS2 |
Minute inclusions, very difficult to detect under 10x magnification by a trained gemologist. |
Very Slightly Included |
VS1, VS2 |
Minute inclusions seen only with difficulty under 10x magnification. |
Slightly Included |
SI1, SI2 |
Inclusions visible under 10x magnification or by unaided eye to an experienced grader. |
Included |
I1, I2, I3 |
Inclusions visible to the naked eye. |
|