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Roger Weller, geology instructor                     

Diamonds, 4 Cs
Tanya Eavenson
Physical Geology
Fall 2005

                                                   Diamonds, The Four Cs

The Four Cís

     The four Cís consist of Carat weight, Cut, Color, and Clarity.  A diamonds price and quality are not only determined by one of the Cís, but by the combination of all the four Cís.  When you are deciding on what type of diamond to buy you need to consider these four Cís.  With this knowledge, you will be able to choose a diamond, which is right for you. 


     A well-cut diamond is created by a skilled craftsman.  The angles and proportions determined by the craftsman are what create the fire and beauty of the diamond.  A diamonds clarity and color can look dull if the diamond is not cut correctly.  The cut is considered the most important of the four Cís.  When a diamond is cut it determines how and how much light is reflected in the diamond.  The cut describes the quality of the diamond, not the shape.  The better the cut the more fire the diamond will have. A diamond can be cut to shallow or to deep, if this happens light will escape out the sides or is lost out the bottom. Text Box: Shallow cut, light is lost out the sides


Text Box: Perfect cut
Light reflects correctly.



Text Box: Deep cut, light is lost out the bottom.




Cut Grades

v      Very Good- Top 15% of the diamonds. Diamond reflects almost all the light that entered.

v      Good- Top 25% of the diamonds. Diamond reflects most of the light.

v      Fair- Top 35% of the diamonds. Diamond reflects some light.

v      Poor- this does not meet the standards for grading. 


The color differences of diamonds are very subtle.  An expert under controlled lighting and conditions determines the color of the diamonds.   Then they are compared to a master set to make sure the grading was right.  The best diamond has no color.  Diamonds come in many different colors, white to faint yellow or brown.  Some very rare colors are pink, blue, and green.  When the diamond has more color in it, there is less fire; there for the color grade is not as good.  

Color Grade: Highest color grade to the lowest

D- Absolutely colorless: extremely rare

E- Colorless: very rare, extremely small traces of color, which can only be detected by an expert.

F- Colorless: high-quality diamond, color found by an expert.

G-H- Near-colorless: color is noticeable only when put next to a better grade diamond.

I-J- Near-colorless: faint color can be seen.

K-Z- Color is noticeable.



Clarity means no inclusions were found in the diamond.  All natural diamonds have some type of flaws created during the crystallization process.  Where, how many, and how large the inclusions are determines the diamonds quality, and price.  The fewer inclusions the more light can pass through the diamond, giving it more fire.  Inclusions are found as white points, dark dots, or feathery cracks.  Blemishes are on the surface of the diamond.  A trained professional determines the clarity of a diamond.  

Clarity Grades

IF- Internally Flawless: No inclusions can be seen under 10 power magnification.

VVS1, VVS2- Very, Very Small inclusions: very few and very small inclusions were found under 10 magnification.

VS- Very Small inclusions: small inclusions were found under 10 power magnification.

SI1, SI2, SI3- Small inclusions: many small inclusions could be seen under 10 power magnification. May also be seen by a naked eye.

I1, I2, I3- Inclusions could be seen under 10 power and by the naked eye.

There are two ways to make a diamond seem better then it is.  Laser drilling is used to remove the black spot in the diamond.  Fracture Filling, is the process of filling the fracture, there for this is not permanent fix.  These diamonds are called clarity enhanced and are a lower price.  When you are looking for a diamond make sure you find out if the diamond has been enhanced.

Carat Weight

Diamonds are divided by points.  One carat has 100 points, one-half carat has 50 points and so on.  Carat total weight (Ct. T.W.) is used to describe the total weight of all the diamonds in the piece of jewelry.  It is harder to find large diamonds, so a 2-carat diamond would be worth double the amount of 2 one-carat diamonds of the same quality.  


Popular Diamond Shapes 
v      Emerald
v      Oval
v      Radiant
v      Princess
      Round Brilliant


When you are looking for a diamond it is important to have the knowledge of choosing one of good quality.  How big the diamond is will not determine if it is a great diamond.  An excellent diamond possesses all the good qualities of the four Cís. 

 Addition from the public:



Bluenile, November 16, 2005,

The Diamond and the 4 Cís, November 25, 2005,íC%20Diamonds/4Cís.htm      

The Four Cís of Diamonds, November 23, 2005,