COLOR
Diamond Color starts from D and ranges down to Z.
The higher the color grading, the more colorless the stone is when put on an off-white sheet paper.
Color grades are categorized as follows:
D,E,F – Colorless
G,H,I,J – Near Colorless
K-M – Faint Yellow
N-R – Very Light Yellow
R-Z – Light Yellow
WHAT ABOUT FLUORESCENCE?
Fluorescence is the amount of ultraviolet light(UV) the stone carries by its nature.
Fluorescence intensity varies from None(N), Faint(F), Medium(M), Strong(S) & Very Strong(VS).
In certain cases, high intensity of fluorescence such as Strong(S) & Very Strong(VS) would give a milky effect and whiter color on the stone.
CLARITY
Clarity involves determining the number, size, relief, nature, and position of these characteristics, as well as how these affect the overall appearance of the stone.
Clarity can be mainly categorized as inclusions & blemishes.
Inclusions are those that stay within/inside the stone
Blemishes are the ones that sticks on the external surface of the stone.
Clarity Grading Scale
Flawless (FL) – No inclusions and no blemishes visible under 10x magnification
Internally Flawless (IF) – No inclusions visible under 10x magnification
Very, Very Slightly Included (VVS1 and VVS2) – Inclusions so slight they are difficult for a skilled grader to see under 10x magnification
Very Slightly Included (VS1 and VS2) – Inclusions are observed with effort under 10x magnification, but can be characterized as minor
Slightly Included (SI1 and SI2) -Inclusions are noticeable under 10x magnification
Included (I1, I2, and I3) – Inclusions are obvious under 10x magnification which may affect transparency and brilliance
CUT
Generally, Cut is misinterpreted as Shapes (Round, Oval, Princess, Emerald, Radiant etc).
Cut is indeed the ability to transmit light & sparkle intensely.
This is the most complex & difficult part among the 4Cs.
Cut can be categorized into 3 sections:
Brightness – Internal and external white light reflected from a diamond
Fire – The scattering of white light into all the colors of the rainbow
Scintillation – The amount of sparkle a diamond produces, and the pattern of light and dark areas caused by reflections within the diamond
CARAT
Carat is the measurement of a diamond’s weight.
The metric “carat” (ct) is defined as 200 milligrams / 0.20 grams.
Each carat (ct) can be subdivided into 100 points / 0.01 carat.
This allows very precise measurements to the hundredth decimal place.
GIA is very strict on the certification process the thousand decimal place has to be exactly “9” in order to be rounded up to the nearest hundredth decimal place.
For example, 2 stones 1.999ct & 1.998ct would be considered 2.00ct & 1.99ct respectively under grading process.