Carat weight is the most objective of the 4 C’s of diamonds as it involves no estimates, comparisons or judgements.

visual effect of carat weight on a diamond's appearance seems fairly obvious: the more a diamond weighs, the larger it will look. However, this is not always the case. As most people in the trade already know, cut proportions can also affect the perceived size of a diamond.

A carat is a unit of measurement used to weigh a diamond. One carat is equal to one fifth of a gram (0.2 gram) or 200 mg. One carat is equal to 100 points or 100 cents

Carat weight is directly related to a diamond's value because (all else being equal) larger diamonds are rarer than smaller ones. As a result, larger diamonds cost more per carat than smaller diamonds (e.g., a 2.00 ct diamond of the same quality can cost more than twice the amount of a 1.00 ct diamond).

The colour of a diamond is one of the vital factors influencing the price of diamond. In diamonds, the best colour is no colour at all. Colourless diamonds are extremely rare, hence making them the most sought after. Contrary to common belief, all diamonds are not truly colourless. They actually come in many different colours - commonly faint yellow or brown. But its colourless diamonds, sometimes called white diamonds, which all other shades are judged against. Colourless grade diamonds are the most valuable with exception to some fancy colours which are again very rare and expensive if their colour is natural.

There is now an internationally recognised colour grading scale which starts at D (colourless), and goes down to Z (light yellow). Each letter grade represents a range of colour and is a measure of how noticeable the colour is. Colourless diamonds and diamonds that are yellow or yellowish brown are grouped into the categories shown below

Colourless diamonds allow the maximum refraction of light thus maximising brilliance. In comparison Off White diamonds absorb light hence inhibiting brilliance.

Intensely coloured diamonds are known as "fancies" or fancy coloured diamond. Natural Fancy Colour Diamonds are rare and can be very expensive. It’s said that out of 10,000 normal diamonds one of them would be a fancy colour diamond. The most popular fancy colour diamond is Yellow. Other colours such as Pink, Blue, purple and Red and can be extremely expensive.
Fancy Coloured Diamond Grading

The colour of a fancy coloured diamond is measured differently to a normal diamonds. The grading scale is based on the intensity of the colour. The GIA fancy colour grading scale is: Faint, Very Light, Light, Fancy Light, Fancy, Fancy Intense, Fancy Vivid, Fancy Deep and Fancy Dark

Diamonds contain naturally occurring impurities known as inclusions. They may occur internally in the form of tiny fractures, feathers, clouds or crystals and externally as scratches and fissures. They are caused by trace minerals and other impurities that may be present or by irregularities in the natural process of diamond formation. Factors determining the clarity of diamonds are - number of inclusions, nature of inclusions (e.g., feathers, clouds, knots, colour), location and size of the inclusions

In addition to internal inclusions, surface irregularities are referred to as blemishes. These two categories of imperfections-inclusions (internal) and blemishes (external)-make up clarity.

Inclusions greatly affect the beauty and value of a diamond because they absorb the light rather than allowing it to be reflected back through the front side of the stone. Consequently fewer the imperfections, the rarer and more valuable the diamond.

Diamonds are graded for clarity on the basis of internal and external imperfections present.

• As the grading decreases the price decreases exponentially. This is because diamonds with greater quality (correspondingly with lesser inclusions) are that much rarer.
• Along with the type and number of inclusions, their position also makes an impact on the value and brilliance of a diamond.
• Fortunately diamonds of all clarity grades and prices, including those with eye visible inclusions can look beautiful. It primarily depends on how well they are cut and other factors
• Contrary to popular belief, higher clarity does not always mean more beautiful. If the inclusions are not visible to the naked eye, a higher clarity does not really improve the appearance of a diamond but rather the rarity and price.

Cut refers to the quality of the proportions, polish and symmetry of a diamond. Of the 4C's, the cut is the aspect most directly influenced by man, whereas the other three C’s are influenced by nature.

Quite often the cut of a diamond is confused with its shape, but it actually is about a diamond's proportions, such as its depth and width and the uniformity of its facets--all characteristics that control brilliance, durability and other features we look for in a diamond.

The brilliance of a diamond depends a lot on its cut. Whatever the shape, a well-cut diamond always reflects better light. Diamonds with perfect colour or clarity also display reduced brilliance if it’s cut poorly.

Diamonds are cut in many shapes but, it is the precision with which facets are polished on to a diamond, which allows it to capture light and release its brilliance and fire.

When a diamond is cut to ideal or proper proportions, light is reflected from one facet to another and then dispersed through the top of the stone. This results in a display of brilliance and fire.

When the cut of a diamond is too shallow, light escapes through the pavilion before it can be reflected.

When the cut of a diamond is too deep, some light escapes through the opposite side of the pavilion.

A polished diamond’s beauty lies in its complex relationship with light: how light strikes the surface, how much enters the diamond, and how, and in what form light returns to your eye.

The result is a display of three attributes. Brightness is the combination of all white light reflecting from the surface and interior of a diamond. Fire is the coloured flashes that can be seen in a diamond. Scintillation describes the sparkle of light you see in a diamond, and the overall pattern of bright and dark areas when you look at a diamond face-up.

A polished diamond’s proportions affect its light performance, which in turn affects its beauty and overall appeal. Diamonds with good proportions optimize the interaction with light, and have good brilliance, fire, and scintillation.

Polish and symmetry are two other important aspects of the cut. Polish describes the smoothness of the diamond's facets (surface conditions), and symmetry refers to alignment of the facets (the exactness of shape and placement of the facets).

To ensure a diamond has good symmetry, each facet must be consistently sized and positioned opposite its corresponding facet. Symmetry refers to the alignment of one part of the diamond to another. The exactness of a finished diamond shape and the placement of its facet constitute symmetry. .. With poor symmetry, light can be misdirected as it enters and exits the diamond.

Polishing is the final step in diamond cutting. Ideally a diamond should be free of any visible polish lines, burn marks, scratches or abrasions under 10 x magnifications. The smoother the polish, the more beautiful and brilliant the diamond will appear. Surface facets of a poorly polished diamond appear blurred or are dull in their sparkle

Inclusions