Diamonds are graded across the world on standard parameters knows as the 4 C’s : Carat, Cut, Colour and Clarity. We’re here to help you understand these details and choose the right solitaire.

Diamond Cut

The cut is an extremely important factor determining the beauty of a diamond. The cut includes the proportions, polish, and symmetry, and these influence the brilliance, fire, and scintillation of a diamond. It is important for a diamond to have well-cut angles and finish for it to sparkle and allow maximum reflection of light. A poorly cut diamond can appear to be dark, dull, and lifeless. It has the greatest overall influence on a diamond's beauty.

According to IGI standards, a round diamond is graded on its Cut (shape), Polish (surface area), and Symmetry (balance in facets) features separately. For fancy shapes, the Symmetry and Polish Features are graded, Cut is not graded.

When a diamond is fashioned from a rough stone, the cutter must balance optimal cut (to achieve maximum scintillation) against maximum yield (to achieve maximum size and weight as possible). Because many customers are willing to pay more for a larger, fair-cut cut diamond than for a slightly smaller, well-cut diamond, there is pressure on the cutter to sacrifice cut for weight. This is why the Cut grade is so important; it allows the purchaser to identify those stones that were cut Fair to Poor in an effort to gain carat weight.

The Diamond Cut Scale Ranges

• Excellent : Highly reflective and proportionately cut.
• Very Good : Very reflective with well-cut facets.
• Good : Most of the light that passes through is reflected back. The proportions are likely to be less ideal than higher-rated diamonds.
• Fair : Light will start to reflect out of the bottom or sides. These diamonds tend to be small so that their lower shine is not as noticeable.
• Poor : Noticeably dull to the naked eye. These diamonds are less proportionate, resulting in a less reflective stone.

Diamond Color

Interestingly, the colour evaluation of diamonds is based on the absence of colour, so when we speak of colour we actually are referring to the degree of colourlessness in a diamond. Many of these colour distinctions are so subtle that they are invisible to the common eye; however, these distinctions make a significant difference in diamond price and quality. While most diamonds are white, not all are truly colourless, they have colour tints. In a white diamond, the presence of a tint is considered undesirable. Diamonds are graded on a Whiteness scale or absence of colour scale. Basically, the whiter or clearer the colour of a diamond, the greater its sparkle and thereby its value.

The IGI has devised a set of guidelines to grade diamond colour ranges from D to Z, with D colour diamonds being rare, totally colourless, and the most expensive. Each letter represents a range of colours based on a diamond's whiteness.

WHICH COLOUR TO CHOOSE?

• The difference in appearance between colourless diamonds and near-colourless diamonds may not be detectable, but the price difference from one colour grade to another can be significant.
• The purists at heart will always want diamonds in the D-F range. By selecting diamonds in the G-I range, however, you can find great value while still achieving a "colourless" look.
• J-K-L colour diamonds can be chosen if you want to buy a larger-sized diamond or a higher clarity diamond within your budget.
• Diamonds with pointed ends, specifically marquise, radiants, pear, and sometimes even princess-shaped diamonds tend to focus the colour on these points. So, you should select diamonds with better colours for these shapes.
  
  

Diamond Clarity

Clarity reflects the purity of a diamond or the inclusions and blemishes in a diamond. The inclusions and blemishes impact a diamond’s ability to let in light and reflect its brilliance. Inclusions are interior irregularities and blemishes are exterior irregularities. These imperfections are not flaws, but rather the natural fingerprint of every diamond. Often, we can see these only under a powerful microscope or jeweler’s loupe, and they do not visibly affect the appearance or beauty of a diamond. Large inclusions can affect the scintillation of a diamond considerably be absorbing the light passing through. Some inclusions are coloured too, the most common one being “Nats”- a black inclusion, which is considerably big, and can be easily spotted by the naked eye. The larger or more numerous the inclusions the less valuable the diamond.

Internationally, diamonds are graded by labs according to the following grades:

• FL Flawless: These diamonds are completely clean and have no inclusions or blemishes detectable under 10x magnification. They are extremely rare and expensive.
• IF Internally Flawless: These diamonds have no detectable inclusions but may have some surface blemishes under 10x magnification. They are very rare and very valuable.
• VVS1/VVS2 Very Very Slightly Included: Inclusions and blemishes are extremely difficult for even a skilled gemologist to detect under 10x magnification, usually visible only under a powerful microscope.
• VS1/VS2 Very Slightly Included: Inclusions and blemishes are detectable under 10x magnification, but are minor flaws that do not impact the diamond's beauty and are totally invisible to the naked eye.
• SI1/SI2 Slightly Included: Inclusions and blemishes are easily noticeable under 10x magnification and may also be visible to the naked eye.
• I1, I2, I3 Included: Inclusions and blemishes are obvious under 10x magnification and typically visible to the naked eye. These flaws may negatively impact the transparency and or brilliance of the diamond.
  

WHAT CLARITY GRADE TO CHOOSE?

Diamonds with the least amount of flaws hold the highest clarity grading. Depending upon one’s budget and preferences, the clarity grade should be chosen. If you want completely clean diamonds, then you can go for VVS1/VVS2. If you want a diamond that is visibly clean to the untrained eye, you can consider VS1 or VS2. If you want a larger-sized diamonds or a better colour within your budget, you may select SI1 or SI2. An "eye-clean" diamond - one that has no imperfections visible to the unaided eye – is an excellent value. SI1 and VS2 diamonds are typically considered clarity grades of great value since their inclusions are minor and invisible to the unaided eye. As diamond size increases, it becomes easier to see the inclusions even with the unaided eye. So consider this while making your choice. It will be much easier to spot the inclusions in a 2.00Ct SI2 as compared to a 0.30Ct SI2.

Diamond Carat

Diamonds are sold by the carat (shown as ct.), which is actually a unit of weight, though most think of a carat in terms of size. A carat is equal to exactly 0.2 grams (about the weight of a paper clip). Important to note that Carat weight is not related to the similar sounding karat, which refers to gold's purity.

Two diamonds of equal carat weight can have very different costs based on other factors. (Such as cut, colour, and clarity.) The carat of a diamond importantly indicates its size which is usually made e.g. a 1 ct round brilliant cut diamond is usually 6.4 mm in diameter. Most women will relate the ct wt. to the size referring to 1,2 or 5 ct stones but the size can vary depending on the shapes as well.

As the carat size of the diamond increases, the diamond's price increases at an increasing rate. Why? Because the larger the diamond, the more increasingly rare it is. Price is not directly proportional to size. So, a 2-carat diamond of certain quality will be priced at more than twice the price of a 1-carat diamond of the same quality.

The size (in mm) of a diamond for a specific shape, is directly proportional to the carat weight of a diamond. See chart below for Round Cut as an example.