Click for Detail

Within weeks, thousands of prospectors from around the world flocked to South Africa in search of diamonds and instant wealth. Within twenty years, South Africa was producing 3 million carats per year of diamonds.

While the initial finds were alluvial, tracing the source upriver led to the discovery of the first kimberlite pipes: the source of the diamonds. A single one of these, the Big Hole in Kimberly, South Africa (and for which the rock kimberlite is named), produced 14 million carats of diamonds in the 42 years of production. Note that 25 million tons of kimberlite were excavated - barely a half-carat of diamond was found in an average ton of ore. Still, this qualifies as an exceptionally rich diamond ore.

No history of the diamond industry would be complete without a description of the man who founded a diamond empire: Cecil Rhodes. From his home in England, he joined his older brother Herbert in South Africa at the age of 17 to help establish a cotton farm. Herbert, however, had gotten the diamond bug and purchased 3 claims in the Kimberly pit. Cecil turned out to be adept at managing the Zulu workers, and Herbert soon sold him his claims and headed off in search of gold. Within two years, Cecil had amassed a small fortune of £10,000 and headed back to England to complete his education at Oxford while leaving the management of his claims to a trusted friend.

Eventually, he returned, and his timing was excellent. There was a world-wide financial panic in 1873 which depressed the prices of diamonds, and at the same time the miners felt their mines were petering out. The yellow ground (weathered kimberlite) which had readily yielded its store of diamonds was underlain by a hard rock, called blue ground (also kimberlite), and most miners believed that they were finished when they reached the hard blue ground. Many went bankrupt, and others sold their claims for a song. Cecil Rhodes believed that the blue ground also held diamonds and that the market would return, so he bought as many claims as he could afford, especially in the De Beers pipe. He named his holdings the De Beers Mining Company, Limited.

He expanded his holdings at every opportunity, including establishing excellent partnerships and outsmarting his greatest rival, Barney Barnato, the man who sank the first deep shaft into the Kimberly pipe. By 1889, Cecil Rhodes had wrested control of 90% of the world's diamond production. He used that position to establish price and distribution controls, and the power of De Beers in the diamond market was essentially unchallenged until the recent rise of Russian diamond mines. It is rumored that De Beers holds tens of millions of carats of diamonds in their vaults to insure that oversupply doesn't quench the market for the stones. However, the new mines in Russia, Australia, and Canada are largely distributed outside of the De Beers control, and consequently they only control perhaps 40% of the world supply. However, they are more profitable than ever.

Note that De Beers established policies and practices to guarantee that De Beers diamonds were conflict-free. The last of his wills established the Rhodes Scholarships for students from the British Colonies, United States, and Germany, regardless of race or religion. He died in 1902 near Cape Town, South Africa.

Diamond is formed at great depth in the earth, between 150 and 300 km below the surface and at great temperatures and pressures. By a kind of volcanic eruption the diamonds were pushed up through volcanic pipes of diamond bearing rock such as kimberlite. With gradual erosion kimberlite chimneys were exposed at the earths surface.

The Ideal Cut Round Brilliant Diamond

The earliest guidelines for diamond cutting were based more on aesthetics than science, but in 1900 the round brilliant had evolved into something very close to its current form. In 1919, Marcel Tolkowsky, a member of a Belgian diamond cutting family, published a short paper entitled Diamond Design. This was the first analysis of diamond cutting based on modern science theories of light behavior.

Despite the fact that Diamond Design was first published in England, Tolkowsky’s design is often called the “American Ideal Cut” because U.S. cutters were the first to produce it in significant quantities. In the 1950’s, AGS adopted Tolkowsky’s model as its standard for grading cut. The only modifications to the basic design were establishing limited ranges for table size, crown height, pavilion depth and girdle thickness. In 1955, the updated model was renamed the AGS Ideal Cut.

The demand for Ideal cut diamonds has substantially increased and today numerous cutters around the world are producing designs loosely referred to as “Ideal Cuts.” The standards for these “ideals” vary significantly, and as a result, the ability to recognize and evaluate diamond cutting variations is even more important today. The popularity of “ideal cuts” and the increased consumer demand for verification of this quality factor, were among the primary reasons for establishing the AGS Laboratory (AGSL). Opened in 1995, the lab has grown quickly because it is the only U.S. facility that addresses cut grading in Diamond Quality Documents. (GIA Gem Trade Laboratory), the primary industry source for diamond quality documentation does not address the issue of cut grade in its reports.

American Gem Society (AGS)

The American Gem Society (AGS) Diamond Grading Laboratory uses a cut grade system that assigns diamonds a cut grade as a number between 0 and 10. The AGS Cut Grade reflects the impact of 3 key elements on a diamonds beauty and value:

proportions -- symmetry -- polish

Proportions are the sizes and angles of the diamond’s main parts. Symmetry is the balance and evenness of its faceting and shape. Polish refers to the diamond’s surface quality, including the presence or absence of characteristics such as abrasions, scratches, nicks and polish wheel lines

The AGS Ideal 0 cut grade represents the very best in diamond cutting.

AGS 0 is only assigned to a diamond in which correct proportions, precise symmetry and fine polish are combined to produce an optimum display of brilliance, scintillation and dispersion. The impression is a harmonious balance between the physical dimensions of the diamond and the optical components of its beauty.

As diamonds fall into grades further from 0 (ideal), their relationship to beauty begins to diminish. For example, a diamond with a cut grade of 1 or 2 (very fine cut) are very close to 0 in appearance. A cut grade 5 diamond has variations that detract significantly from overall appeal. It may appear somewhat “washed out” or slightly dark through the center. Cut grades 10 are the worst examples of proportioning, symmetry and polish; so they have little visual “life.”

FL-Flawless
These stones have no imperfections inside or on the outside of the stone under the magnification of a loupe of 10X magnification.

IF-Internally Flawless
This grade is awarded to diamonds with no internal flaws and only minor external blemishes. Nicks pits or girdle roughness, not on the table, which could be removed in re-polishing.

VVS1 , VVS2 - Very Very Slightly Imperfect
These stones have very, very small inclusions, which are extremely difficult to see under a loupe of 10X magnification.

VS1, VS2 - Very Slightly Imperfect
These stones have very small inclusions, which are slightly difficult to see under a loupe of 10X magnification.

SI1,SI2-Slightly Imperfect
These stones have inclusions, which are fairly easy to see under with a 10X magnification, and can be seen with the naked eye.

I1, I2, and I3-Imperfect
These stones have inclusions ranging from eye visible to very easily seen to the naked eye.


Internally Flawless: No internal blemishes are visible under 10x magnification Very very slightly included: No internal blemishes are visible under 10x magnification Very slightly included: Blemishes and inclusions difficult to locate under 10x magnification

Slightly included: Blemishes and inclusions easy to locate under 10x magnification Imperfect: Blemishes and inclusions easy to locate under 10x magnification and naked eye Imperfect: Blemishes and inclusions easy to locate with naked eye

Flaws are caused by a shift in the pressure and or temperature during the time when the diamond is being formed. There are many types of imperfections, internal inclusions and external flaws.

Types of Internal flaws or Inclusions
Pinpoints - A small usually whitish dot that is difficult to see. There can be a number of pinpoints - cluster -or a cloud of pinpoints.

Dark Spot - A small crystal inclusion or thin flat inclusion that reflects the light like a mirror.

Colorless crystal - This is a small crystal of diamond, and sometimes-another mineral.

Cleavage - A small cleavage is a crack that has a flat plane, which if struck in a certain direction, could cause the diamond to split.

Feather - This is another name for crack. A feather is not dangerous if small and does not open through a facet.

Bearding or girdle fringes - Result from hastiness in the bruiting process when giving the diamond its initial shape in the cutting process.

Growth or grain lines - These can only be seen when rotating the diamond slowly during examination. They appear and disappear usually instantaneously and will appear in groups.

Knaat or twin lines - Slightly raised dot with a trail resembling a comet.

Laser treatment - A laser is used to make flaws less visible. A black spot can be vaporized and will disappear leaving a void in the diamond.

Types of External flaws or Blemishes
Natural - This usually occurs on the girdle and looks like a rough, unpolished area. A natural is a remnant of the original skin of the diamond. Indicates a shortage of rough or that the cutter made the largest acceptable diamond from the material he had to work with.

Nick - This is a small chip, usually on the girdle and can be caused by wear. Sometimes a nick or chip can be seen on the edge of a facet.

Girdle roughness - This blemish appears as crisscrossed lines, and can be removed by re-polishing.

Pitts or cavities - Pits or holes on the table facets.

Scratch - A scratch is usually a minor defect that can be removed by re-polishing.

Polishing lines - Many diamonds exhibit polishing lines and are the result of badly maintained polishing wheels.

Abraded or rough culets - The culet has been chipped or poorly finished.

The clarity grade can have a significant effect on the value of a diamond.

Diamonds are sold by carat, (ct.) not to be confused with karat, (kt.), which in the United States refers to gold quality. The carat is a unit of weight, not size. This is an important concept since the specific gravity varies among different minerals. For example, Emerald has a lower specific gravity than diamond. A one-carat emerald is 20% larger than a one-carat diamond. Ruby has a higher specific gravity than diamond, which makes a one-carat ruby smaller than a one-carat diamond.

Everyone first asks what size is the diamond? Most times color, cut, and clarity seem of secondary importance. It is very important to realize that small shifts in quality and size can make tremendous differences in value. As the size of the diamond increases, the price increases significantly. Diamonds weighing two-carats will sell for far more per carat than one-carat diamonds. As you will see in the chart below, the price of a diamond tends to increase exponentially as the size increases.