How a Diamond’s Value is Measured

A diamond’s value is measured by the 4 C’s: 

Clarity, Cut, Colour, Carat.

 The Gemological Institute of America known as GIA, developed and introduced the International Diamond Grading System in 1953. 

This system was created to stop the confusion and help everyone who deals, sells or buys diamonds to have a common language when talking about a diamond’s colour and clarity as this system helps to understand and assess a diamond’s overall quality.  

The Four C’s affect value according to rarity. 

A diamond’s value is based on its own unique combination of the 4 C’s. 

1. Clarity

Very few diamonds are absolutely perfect. Diamonds have internal features called inclusions and surface irregularities called blemishes.
Inclusions normally have more impact on a diamond’s value, but they have positive effects as well: 

They help gemologists separate diamonds from simulants as their inclusions look different.

Because no 2 diamonds have exactly the same clarity characteristics, they help identify individual stones.

They provide scientists with valuable information about how diamonds form.

GIA Clarity Scale: 

Flawless – No inclusions and no blemishes

 IF – only blemishes no inclusions 

VVS1, 2 – minute inclusions that its difficult even for a skilled grader to see 

VS1, 2 – minor inclusions that range to difficult to somewhat easy for see for a trained grader.

 SI1, 2 – contain inclusions that are easy to see for a trained grader. 

I1, 2, 3 – contain inclusions that are obvious for a trained grader to see  

Flawless diamonds are so rare one might never encounter one in his whole career. On the other end of the scale inclusions might be visible to the unaided eye. 

Stones that make up the bulk of the retail diamond market fall between the 2 extremes. They usually have inclusions that are visible only under magnification. 

The effect of clarity characteristics on the clarity grade is based on their:

Size, Number, Position, Nature, Colour or Relief.

 Size: Generally the larger and more visible a clarity characteristic is the lower the diamond’s clarity grade will be.

 Number: More clarity characteristic can mean a lower grade, but grades are normally set by how readily you can see them not by counting them. Few tiny pinpoints can still be VVS. 

Position: inclusions under the table effect the grade much more then inclusions under the star facets.  

Nature: the nature or type of a clarity characteristic tells your wither its an inclusion or blemish and if it poses any risk to the stone. Most don’t as if a stone had durability problems it doesn’t survive the friction and pressure of the cutting process. 

The effect of an inclusion and durability is determined by its size and location.

Relief: is the contrast between the colour and the gem. The more difference there is the more it effects the grade. 

2. Colour

GIA colour grading system beings with D and continues through the alphabet through to Z.  

The reason why it starts at D is to be distinguished from all the systems that came before it which used vaguely defined trade terms such as A or AAA colour.  

D colour diamond is considered as top colour and needless to say its very rare and expensive. At the other end of the scale there’s Z.

 Many people think of diamonds as colourless, in reality truly colourless diamonds are rare.  

Colour grading is based on the absence of colour.

D-E-F grades are considered colourless; 

G-H-I-J grades are near-colourless: Diamonds with these grades have slight traces of colour that aren’t noticeable to the untrained eye when diamonds are face up.

 K-L-M are faint yellow. These show very faint yellow tints.

 N through R are considered very light yellow. And also look very light yellow. 

S through Z are light yellow they show substantial colour.

 Once a diamond goes beyond the Z colour range, its classified as Fancy Yellow, which causes the price to rise.. (canary diamonds)

 Many people are unaware that diamonds come in a wide variety of exotic colours.

 Some of the most rare colours are Red, Purple and green.

 With fancy coloured diamonds more colour usually means higher value  

The brightest and purest colours are the most desirable and command very high prices. 

3. Cut

The qualities that determine a diamonds rarity, are, for the most part, determined by nature. But a diamond’s cut and shape, the qualities that determine a diamond’s beauty, are entirely in the hands of the diamond cutter.

 The artisan cuts a diamond to make the best use of light. When a diamond is cut to proper proportions, light is refracted from one facet to another, then dispersed (or returned) through the top of the diamond.

 If, on the other hand, the cut is poor, brilliance is sacrificed. For example, too deep a cut allows some light to escape through the opposite side of the diamond. If the cut is too shallow, light escapes through the bottom of the diamond before it can be reflected. Also, if the faceting pattern is not perfectly symmetrical, light will not bounce correctly from facet to facet. 

A well-cut diamond can make light perform in breathtaking ways, resulting in a magnificent display of 3 important diamond attributes: 

Brilliance, Fire, Scintillation

Brilliance: The brightness created by the combination of all the white light reflections from the surface and the inside of a polished diamond.

Fire: The flashes of colour.

Scintillation: The flashes of light you see when the diamond, the light or the observer moves. 

Brilliant Cut                        Is a general term for gems of any shape with facets that are mostly triangular or kite shaped and that radiate from the center.

 General info about cuts:

The Standard Round Brilliant – 57/58 facets. 

Shapes other then round - Fancy Cuts

Some tend to prefer fancy cuts for larger diamonds.

 Brilliant cuts generally show more fire then step cuts but step cuts usually show colour better.

 GIA grades cut and finish as excellent, very good, good, fair, poor 

4. Carat Weight

A Diamond’s weight is measured by carats and it is an extremely precise weight measure. No wonder since even the smallest fraction makes a price difference!

 One carat – 1/5 0.200 of a gram. 

Metric carat is divided into 100 points. 1.00 / 0.75 / 0.50 / 0.25

 Double the weight isn’t double value but more – this is due to rarity.

Bigger diamonds are much more rare!

 1.00ct LM1000 – 2.00 not Lm2000 but Lm2500

 Diamonds are also the most durable gemstones. Durability is measured from 1 to 10 on Moh’s Scale where 10 is the most durable 

Diamond is 10 on Moh’s scale and is the only one.

It has extremely high resistance to scathing

Excellent Luster - Adamantine