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Roger Weller, geology instructor

Diamonds-The Four C's
Mark Alexander
Fall 2005

Buying a Diamond

    So you have decided to purchase a diamond for your significant other. This may be one of the largest single purchase other then a car or home, which you will have to make. The average amount one will spend is about three monthís salary. Listed in the following pages are some of the basics you need to know about how to buy a diamond and what the 4Cís are.



The 4 Cís



1. The Cut

             The cut of the diamond is in reference to its proportions. Of the 4cís the cut is a property defined and influences by man.  A majority of the time the cut of the diamond is confused with the shape.  Depending on the use of the diamond, will define its shape.  Whatever the shape is the as long as the cut is good it will reflect light.  The better the cut, the better the refraction of light.  This is what gives you that fire and brilliance when exposed to light.  Diamonds are usually cut with 58 facets (the polished plane surfaces of a gemstone); these facets follow a mathematical formula and are placed at specific angles in relation to each other.  

This picture may help you understand the following terms.


   Girdle: The girdle is the edge or border of the stone that forms its perimeter;
      it is the edge formed where the top portion of the stone meets the bottom portion-its  "dividing line."
     This is the part usually grasped by the prongs of a setting.

Crown: The crown is also called the top of the stone. This is simply the upper portion of the stone, the part above the girdle.

   Pavilion: The pavilion is the bottom portion of the stone, the part from the girdle to the point at the bottom.

   Cutlet: The culet refers to the "point" at the bottom, which is really not a point but another tiny facet. The smaller the culet the better. Today, many diamonds are cut without a culet, and colored gemstones are often cut in styles that lack the culet.

 Table: The table is the large, flat plane (facet) at the very top of the stone. It is the largest facet on a stone, often called the face. The term table spread is used to describe the width of the table facet, often expressed as a percentage of the total width of the stone.


            The main centers for cutting diamonds are located in New York, Antwerp, and Tel Aviv.  Most cutting of very small diamonds (melee) is done in India.  U.S. cutters typically confine their work to gems over 1/8 carat, with the smaller gems being cut in Israel and Antwerp.  Antwerp cutters are renowned for well-made fancy cuts.  Smaller cutting centers exist in Amsterdam, London, Johannesburg, and San Juan, Puerto Rico.  When diamonds are cut to the correct proportions they are then categorized as Ideal, Excellent and very good.


            In addition to the cut, the shape is another important part.  Depending the taste of the individual you are making this purchase for will define the shape. Throughout time, the shape of diamonds has increased and decreased the value. Nevertheless, you are not buying this for an investment no matter how many times you may tell yourself that.  Below are the typical shapes.




2. The Clarity


            All diamonds have inclusions of carbon. Depending on the amount you can see with the naked eye will affect the cost. There are several grading systems used to describe clarity.  By far, the two most popular are the Gemological Institute of America (G.I.A.) scale 
or the Belgium Diamond High Council (HRD) standard,
which ranks diamonds as:


FL: Completely Flawless (Unless you are a Count or own a small country this may be out of reach)
IF: Internally flawless; only external flaws are present, which can be removed by further polishing the stone.

Very Very Small Inclusions
VVS1-VVS2: Only an expert can detect flaws with a 10X microscope. By definition, if an expert can see a flaw from the top of the diamond, it is a VVS2. Otherwise, if an expert can only detect flaws when viewing the bottom of the stone, then it is a VVS1. (This is what I would personally spend the extra money for)

Very Small Inclusions
VSA-VS2: You can see flaws with a 10X microscope, but it takes a long time (more than about 10 seconds)

Small Inclusions
SI1-SI2: You can see flaws with a 10X microscope.

I1-I3: You can see flaws with the naked eye. (This will not make your significant other happy.  Consider spending more money to get a higher clarity or go with a smaller carat.)



3. The Color

Diamonds ideally should have no color at all, pure as a drop of water. The GIA has come up with the following scale.



            The GIA uses a machine called a colorimeter for color grading, but the human eye is no substitute for color. Again, this is an important factor in buying a diamond. I would suggest going no lower then a K on the color scale. Anything below that will really look yellow.

            The colors D, E, and F can all be grouped as exceptionally fine, rare colors and may be referred to as "colorless",           exceptional white", or "rare white", as they are often described by diamond dealers.
G and H may be referred to as "fine white" or "rare white."  These grades are all considered very fine.
I and J colors are slightly more tinted than G and H, and sell for less, but diamonds possessing color grades from G through J are all fine colors and are classified as "near colorless."
K and L show a stronger tint of yellow or brown, but settings can often mask the tint.
Grades M-Z will show progressively more and more tint of yellowish or brownish color.
Grades D-J seem to have a better resale potential than grades K-Z. This does not mean, however, that diamonds having less rare color grades are less beautiful or desirable.




4. The Carat (ct)

           Not to be confused with karat (kt) which refers to gold quality in the United States. The carat is a unit of weight, not size. Since 1913, most countries have agreed that a carat weighs 200 milligrams, or 1/5 gram.  Now, the size of the person's finger will determine the carat needed to look correct. Remember, having a gaudy large diamond that is a W color does not look very good.  So go with what you can afford.  On average, I would say 1ct is a good place to start.  If you can afford a larger weight, great.  Jjust remember that you can always add begets on the side of the setting to add to the total weight of the diamonds.



Now what shall you place the diamond in?
Well you have a few types of settings the platform or stage where the diamond sits.



Platinum                                                          White Gold




 Yellow gold




            Now that you have learned about the 4 Cís you still have a lot of work to do.

First, you need to find out what your budget is.

Second, find out what style diamond is desired (the shape)

Determine how large the finger is that the diamond ring is being placed on to have the carat look correct.

Lastly, make sure you get the diamond GIA certified.  Also, do not forget insurance on that puppy in the event it is dropped it down the sink.


For additional information, please check out the following pages as well.




Photo Credits:

The Gemological institute of America:


The Diamond

Midwest Diamond Imports:


Works sited:

The Gemological institute of America:


The Diamond

Midwest Diamond Imports: