The cut grade measures how the individual proportions combine to effect the beauty of a diamond.
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.
Diamonds with an Excellent or Very Good cut grade will allow a maximum amount of light to be returned to the observer and therefore have the highest degree of brightness, fire(rainbow colours) and scintillation(sparkle).
The international unit of weight used for measuring diamonds and gemstones, 1 carat is equal to 200 milligrams, or 0.2 grams. A specific measurement of a diamond’s weight, carat weight alone may not accurately represent a diamond’s visual size.
Most diamonds are colourless to near colourless. The highest colour grade that exists is D or colourless and extends to Z being light yellow.
Diamonds in the D to F colour grades are considered colourless. Diamonds in the G to J colour grades are considered near colourless.
Diamonds are valued on how closely they approach colourlessness – the less colour, the higher their value. (The exception to this is a fancy colour diamond, such as pinks and blues, with lie outside this colour range.)
All diamonds contain imperfections. Because diamonds are formed deep within the earth, under extreme heat and pressure, they often contain unique birthmarks, either internal (inclusions) or external (blemishes). Clarity refers to the absence of these inclusions and blemishes. Diamonds without these marks 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).
The GIA Clarity Scale contains 11 grades, with most diamonds falling into the VS (very slightly included) or SI (slightly included) categories. In determining a clarity grade, the GIA system considers the size, nature, position, color or relief, and quantity of clarity characteristics visible under 10× magnification.
No inclusions or blemishes are visible to a skilled grader using 10× magnification
Internally Flawless (IF)
No inclusions and only blemishes are visible to a skilled grader using 10× magnification
Very, Very Slightly Included (VVS1 and VVS2) - Inclusions are difficult for a skilled grader to see under 10× magnification
Very Slightly Included (VS1 and VS2)
Inclusions are minor and range from difficult to somewhat easy for a skilled grader to see under 10x magnification
Slightly Included (SI1 and SI2)
Inclusions are noticeable to a skilled grader under 10x magnification
Included (I1, I2, and I3)
Inclusions are obvious under 10× magnification and may affect transparency and brilliance