Gemstones, Birthstones, Gemstone Jewelry


The famous 4 C’s

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.

Diamond Shape

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.

Diamond Cuts

The most popular shapes of diamonds are

Diamond Shapes

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 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






No internal or external flaws. Very rare and precious.

Internally Flawless


No internal flaws. Some minute external flaws. Again very rare and precious.

Very Very Slightly Included


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.


I1, I2, I3

Inclusions visible to the naked eye.


Color refers to the natural body color of a diamond.

Colorless diamond

Diamond in its purest form is made of only carbon atoms. These chemically and structurally perfect diamonds are colorless and are a rarity. All the other diamonds occur with the tints of yellow or brown. Closer is the color of the diamond to colorless, better is the color, rarer is the stone. GIA grades diamonds according to their color from D to Z, D being the best and colorless.

Natural colored diamonds

Diamonds are believed to be colorless. But, in fact natural diamonds occur in just about every color one could imagine. Blue, orange, gray, pink, red, black and green are to name but a few. Color is the most important factor that affects the quality and the value of these diamonds. When the color gets more prominent these diamonds are referred to as fancy diamonds.

These natural colored diamonds depending on the intensity of color are graded as – Faint, Very Light, Light, Fancy Light, Fancy, Fancy Dark, Fancy Intense, Fancy Deep, and Fancy Vivid.


Many diamonds when exposed to ultra violet light emit a visible light called fluorescence. Although diamonds can fluoresce any color, but the most common are white, blue and yellow. Ultra violet light is invisible to naked eyes but they are even present in the sunlight.

Generally this characteristic has very little effect on the value of diamond. However, if the diamond displays strong yellow fluorescence, it can deter its value as it makes it appear less whitish. And, If the diamond displays strong blue fluorescence, it may make the stone appear whiter in certain light and hence increases the value.


Diamonds are sold by their weight, carat. One carat is one fifth of a gram (0.20 gram) or 200 milligrams. Large diamonds are much rarer than the smaller ones and that is exactly why they commend greater price. It is due to the same reason that a single large diamond is much more valuable that a number of smaller ones that equals the weight of the large diamond.

Depending on its shape, a diamond of the same weight may appear bigger or smaller.

Combination of the 4 C’s

All of these 4C’s play an important part in giving diamond its durability, brilliance, fire, and perfection. Together the 4C’s determine the 5th C of a diamond, that is, the ‘Cost’. Although each of them is important but then some influence the beauty of a diamond more than others and hence it is important that when buying a diamond one try to find the right combination of these - One that meets your emotional as well as financial needs.