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Diamond Education

The 4C's

We will start on saying that like most of the people know , every diamond is UNIQUE, and for this Sky Moon Diamonds want to help their client's to understand the diamond's characteristics and do a better choice when they buy.

Below you can find the GIA's individual 4Cs videos, each of 1-minute that explain each of the 4C's - CUT, CLARITY, COLOR, CARAT WEIGHT and the GIA diamonds-grading process.


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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 colour 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 colours 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.


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Because diamonds formed deep within the earth, under extreme heat and pressure, they often contain unique birthmarks, either internal (inclusions) or external (blemishes).

Diamond clarity refers to the absence of these inclusions and blemishes. Diamonds without these birthmarks are rare, and rarity affects a diamond’s value. Using the GIA International Diamond Grading System™, diamonds are assigned a clarity grade that ranges from flawless (FL) to diamonds with obvious inclusions (I3).

Every diamond is unique. None is absolutely perfect under 10× magnification, although some come close. Known as Flawless diamonds, these are exceptionally rare. Most jewellers have never even seen one.


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Diamond colour is all about what you can’t see. Diamonds are valued by how closely they approach colourlessness: the less colour, the higher their value. (The exception to this is fancy colour diamonds, such as pinks and blues, which lie outside this colour range.) Most diamonds found in jewellery shops run from colourless to near-colourless, with slight hints of yellow or brown.

GIA’s colour-grading scale for diamonds is the industry standard. The scale begins with the letter D, representing colourless, and continues with increasing presence of colour to the letter Z, or light yellow or brown. Each letter grade has a clearly defined range of colour appearance. Diamonds are colour-graded by comparing them to stones of known colour under controlled lighting and precise viewing conditions.

Many of these colour distinctions are so subtle as to be invisible to the untrained eye. But these slight differences make a very great difference in diamond quality and price.


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Diamonds and other gemstones are weighed in metric carats: one carat is equal to 0.2 grams, about the same weight as a paperclip. (Don’t confuse carat with karat, as in “18K gold”, which refers to gold purity.)

Just as a pound is divided into 100 pennies, a carat is divided into 100 points. For example, a 50-point diamond weighs 0.50 carats. But two diamonds of equal weight can have very different values, depending on the other members of the Four C’s: clarity, colour and cut. The majority of diamonds used in fine jewellery weigh one carat or less.

Because even a fraction of a carat can make a considerable difference in cost, precision is crucial. In the diamond industry, weight is often measured to the hundred thousandths of a carat, and rounded to a hundredth of a carat.  Diamond weights greater than one carat are expressed in carats and decimals. (For instance, a 1.08 ct. stone would be described as “one point oh eight carats” or “one oh eight”.)