The Quality Parameters Of Diamonds

4C's D-E-F Diamond Caratage Diamond Clarity Diamond Color Diamond Cut Diamond Grade Diamond Quality VVS

“Woooow what an amazing diamond ring.”  “Diamond earring is shining so much, it is lightening up your face.”  This is the typical reaction when people see good quality diamond jewelry. Buying more expensive diamond jewelry does not necessarily mean that you are buying better diamonds that will mesmerize your friends and family.   

The quality of the diamond is determined by its 4 C’s namely the Colour, Clarity, Cut, and Cartage.

Colour is the degree of hue in a diamond while clarity refers to impurities or fractures in the diamond.  These two factors define the quality of the mined diamond and are beyond the control of man.  Both have a role to play in the ‘wow’ factor of a diamond jewelry.

Cut, on the other hand, is man-made factor. It is dependent on the skills of a diamond cutter on one hand and the trade-off between the optimal angles for maximum light reflection and the desire to maximize the yield from the rough stone.  The quality of the cut will define the lustre and fire of a diamondCarat weight simply refers to how big a diamond is, in other words, its size and weight. One carat is equal to 200 milligrams

We have detailed these 4C’s below for a basic understanding of how the value of a diamond is determined and what you should look for in diamonds when buying diamond jewelry. 

Colour: An ideal diamond is a colorless diamond, free form any taint or hue. Lesser the intensity of hue more will be its value as colorless diamonds are very rare and not normally found.  With this as a base principle, diamonds are graded on their intensities of hue. 10 grades have been identified for the color starting with D – colorless or hue-free diamond – down to M – faint color or pale hue is visible.  As the taint of color increases the grade of the color goes down through E, F, G, H, I, J, K, L, M.  As a rule of thumb, when buying diamond jewelry, the following can be used as a guide.  These do not refer to trade semantics but are an attempt to explain the diamond color to a non-technical diamond jewelry buyer.

D-E-F:  Exceptionally white diamonds 

G:  White Diamonds

H:  Less White Diamonds

I:  Off White Diamonds

J:  Faintly Tainted Diamonds

K-L-M: Evidently Tainted Diamonds


Clarity:  Diamonds by nature contain impurities like black spots, fractures, clouds, milky patches, grains, etc.  They mar the beauty of a diamond and thus diminish its quality and value. The ‘Internally Flawless - IF’ is the grade assigned to the diamond that is free from any internal impurity.  This is the highest a clarity can be.   Below this, based on the size, position and type of impurity present in the diamond 10 grades – VVS1, VVS2, VS1, VS2, SI1, SI2, SI3, I1, I2 I3 – have been made.  They have been categorized as follows:    These, are again near objective grades evolved by GIA (Gemmological Institute of America) and followed by other gem laboratories to grade the clarity of diamonds.

IF:  Ideally Clean

VVS1-VVS2:  Clean

VS1-VS2:  Nearly Clean

SI1-SI2-SI3:  Visibly Impure

I1-I2-I3:  Totally Impure

Again, these terms used, are no substitute for the exact terminology but are loosely used to map the real-life experience of a layman who is not equipped with the grading skills.

Cut:  This is a man-made parameter that affects the luster of the diamonds and consequently the price. The cut is graded from the IDEAL cut or excellent to Poor. The five grades are:  Excellent, Very Good, Good, Fair, Poor.  The cut of the diamond is evaluated on three parameters of Proportion, Symmetry, and Polish.

As said earlier, the cut can single-handedly make or break a diamond.  Better the cut of a diamond is, higher will be its luster or fire and hence more expensive the diamond will be.

This is the most ignored parameter while buying jewelry but effects the beauty of the diamond jewelry, nonetheless.  Quality of cut should not be mixed with the type of cuts such as Hearts, Marquise, Pear, Round, etc.  These define the shape of diamonds and not how well the diamond has been shaped.   

Carat Weight:  Carat weight is used to define the weight of the diamond ie. the size of the diamond.  In ordinary parlance, if two diamonds have the same color, clarity, and cut, the bigger diamond will have a higher value. 

Bigger the diamond, higher will be the price.  And price increases exponentially as bigger sizes are rare to find.  Thus, one diamond weighing one carat maybe 5 times or more the combined value of 10 diamonds weighing one carat and having the same Colour, Clarity, and Cut.

We have tried to explain at a very basic-level what factors determine the value of diamonds.  This can be used as an indicative guide by customers while shopping for diamond jewelry.  However, it will be highly recommended to research more and read technical material (books and papers) if one wishes to increase their understanding of these factors.