Tuesday, August 24, 2004

Amy Sittler, Co-op Student,
Elmira District Secondary School

The diamond

The diamond is a crystalline form of carbon, and natural diamond is the hardest known mineral there is. The most common form is the octahedron, but other forms are cubes and irregular masses. 

The carat

Diamonds are measured in carats. A carat is 0.2 grams. The word comes from the Arabic kirat. One carat is divided into 100 "points" so that a diamond of 75 points weighs 0.75 carats. The carat weight is the most obvious factor in determining the value of a diamond. Although, the quality of the diamond is also very important. 

Kimberite pipes

These pipes of volcanic rock are where diamonds are found. The way to find diamonds in these pipes is to search for indicators of diamonds, not the diamonds themselves. Certain garnets, in particular red garnets may indicate the presence of diamonds.

LEFT: Courtney Keenan, Aurora College, Yellowknife, cuts a diamond at the Prospectors and Developer's Conference in March 2004. Aurora College has programs on diamond mining, cutting and polishing.

Courtney Keenan cutting a diamond

Cutting and polishing of gems

A rough diamond looks like a piece of frosted broken glass. In order to become a piece of desirable jewelry the raw diamond has to be cut and polished. To cleave a diamond properly a small groove must be made in the diamond surface. Only diamond itself can cut another diamond since it is so hard. The process begins by placing a stationary diamond in contact with a diamond revolving on a lathe, or using a diamond saw while cutting against the grain of the diamond. The diamond saw is made of a paper thin disk of phosphor bronze spinning at more than 4000 revolutions per minute. The cutting edge is made of diamond powder mixed with olive oil. Then, after a groove is created in the rough diamond, a metal wedge is inserted into the groove and hammered once with a mallet to split the diamond. Facets are then cut at precise angles, to make the diamond refract all the colours of the rainbow. Diamonds can be cut into round, pear, or square shapes. The most popular cut is the brilliant cut with 58 facets. The final stage is to polish and clean the diamond. Only about 50% of the rough diamond is actually used in the gem quality diamonds.

Uses for diamonds

Diamond use can be split into two categories, gem and industrial diamonds. Gem Diamonds are prized for their:

  • Brilliance - which is the ability to reflect light back to the eye
  • Fire - the ability to refract or bend light rays, and to disperse light into the separate colours of the spectrum
  • Scintillation - the ability to "twinkle" when the diamond is moved 

The way a diamond is cut will determine the degree to which it will exhibit these characteristics. 

Industrial diamonds are the most important industrial abrasive. They are hard enough to cut superhard materials with speed, precision, and economy. Many of the industrial diamonds are synthetically produced, but at very high costs. The uses of diamonds industrially are: 

  • Lapidary for polishing or grinding optics, gems and glass
  • Drill bits
  • Saws for cutting resistant materials
  • Shaping very fine wires or to cover turning, boring, and milling tools
  • Surgical equipment 

Diamonds in industry

Diamond studded rotary bits are used to drill oil wells, and for mining minerals and building tunnels, for things like subways and highways, etc. Low-grade diamonds are crushed to dust in different grain sizes; this is used as an abrasive powder. The powder is also used to polish and cut gems, including diamonds. There are also diamond-tipped glasscutters, and glass etching pencils. Diamonds can also cut thick wire into thin wire. Synthesized diamonds are also used for industrial purposes. In the late 1980s the technology was developed to use diamond coatings on surfaces. These coatings can be used to cool integrated circuits as a whole instead of cooling each part individually. Another use for the coating may be in prosthetic devices and biosensors. 

Man-made diamonds

There are man-made substitutes that resemble diamonds in their appearance, like cubic zirconia, but cost much less. These laboratory-created gemstones and man-made diamonds are sometimes hard to distinguish from natural ones. Imitation diamonds have more fire (flashes of colour) but sparkle slightly less than real diamonds, and have become popular as an alternative to real diamonds. 


A LifeGem is a certified, high quality diamond created from the carbon out of cremated remains. This is a unique and timeless way to remember your loved ones, and the life they lived. The process involves capturing the carbon from cremated remains, which is then heated to extremely high temperatures under special conditions. The carbon is removed at this point, and is converted into graphite. Then the graphite is placed into a diamond press which imitates the forces of nature that create a diamond- heat and pressure. The final step is the cutting, and this entire process takes about 18 weeks, a far cry from the millions of years it takes to make a real diamond. "Like the memory of a loved one, a diamond lasts forever." 

Famous large diamonds

The largest rough diamond ever found was the Cullinan diamond. It was found in South Africa in 1905 and it weighed 3,106 carats. There have been many other large diamond finds, including the Excelsior in 1893. It weighed 995.2 carats and was also found in South Africa. The Star of Sierra Leone came from Sierra Leone in 1972 and weighed 969.8 carats. 

Blood diamonds

Blood Diamonds, or conflict diamonds are defined as, "diamonds that originate from areas under control of forces that are in opposition to elected and internationally recognized govern-ments". The presence of terrorist groups in diamond-rich countries is funded by sale of "blood" diamonds. Sierra Leone is suffering from conflict caused by the availability of diamonds. Other minerals also fund similar conflict, such as Coltan (Columbium-Tantalum) in the Congo.

emerald-cut stone

ABOVE: This emerald-cut stone, cut by Courtney, is 0.75 carats.

The four C's of diamonds

CARAT-WEIGHT: The weight/size of a diamond is measured in Carats. One carat is divided into one hundred segments called "points". As in the decimal system, one hundred and twenty five points equals one and a quarter carats. 

CLARITY: This is the degree to which a diamond is free of inclusions. Where the inclusions lay, their size, their type, all are factors which determine the value of the stone. 

COLOUR: This is another aspect where scarcity determines value. Colourless diamonds are extremely scarce in nature and they are representative of the peak of colour grades. 

CUT: Today the art of diamond cutting has been refined to precise mathematical formulae. Most diamonds today are cut with 58 facets. A good cut is determined by its light-reflecting properties and its light dispersion. 

Diamond Cartels 
The problem with diamonds isn't their scarcity, but actually their controlled availability in the marketplace. What cartels do is puts a hold on production to keep the prices of diamonds high and to maintain a strong monopoly. This is something the De Beers diamond cartel knows well. The cartel has stifled the flow of gem quality diamonds from sources that are not under its owner-ship or control, using a variety of methods. 

Famous Diamonds

  • The Blue Hope Diamond: 45.52 carats- This is a dark, steely blue stone from India. It is named the Hope Diamond after one of its owners, Henry Philip Hope. This diamond is famous for its bad luck. It is a feature at the Smithsonian museum.
  • The Koh-I-Noor (Mountain of Light): 105.60 carats, originally 186 carats- This oval cut diamond dates back through legend before the time of Christ. It was said that whoever owned this diamond ruled the world.
  • The Cullinan Diamonds: 3,106 carats (original rough)- This is the largest gem quality diamond that was ever found, discovered on January 26, 1905 in South Africa. It was noted for its exquisite colour and exceptional purity. It is thought that since the stone had a surprisingly smooth surface on one side it was only part of a larger diamond that was broken off in a weathering process. The Cullinan I is known as the Great Star of Africa weighing 530.20 carats, and the Cullinan II is the Lesser Star of Africa at 317.40 carats.
  • The Regent: 140.50 carats- A stunning gem with a light blue tinge, that is considered the most perfectly cut of all the celebrated old diamonds.
  • The Centenary: 273.85 carats- On the 100-year anniversary of De Beers in 1988, they chanced upon finding a 599 carat diamond, in the rough. After three years of cutting, it was known as the largest modern-cut, flawless diamond.
  • The Orlov: 300 carats (original rough)- The shape of this gem has been likened to the half of a pigeon's egg. It has about 180 facets, and is mounted in the Imperial Sceptre.
  • The Idol's Eye: 79.20 carats- A flattened, pear-shaped stone about the size of a bantam's egg that was once set in the eye of an idol, but was stolen.
  • The Taylor-Burton: 69.42 carats- A spectacular pear-shaped diamond bought by Richard Burton for his fifth wife, Elizabeth Taylor, as a gift.
  • The Sancy: 55 carats- This is a pear-shaped diamond that was named after its owner Seigneur de Sancy.
  • The Dresden Green: 41 carats- This almond shaped stone is the largest apple-green diamond known. The green colour is attributed to the stone's close contact to a radioactive source at some point in its lifetime. Other than its colour it is famous for its elongated shape.
  • The Jubilee: 245.33 carats- A magnificent, colourless cushion-cut diamond that once ranked the sixth largest in the world. Many gemologists considered the Jubilee to be the most perfectly cut of all large diamonds. The facets are so exact that the diamond can be balanced on the culet point, which measures less than 2 millimetres across.


  • UC Berekeley.
  • "Not forever." Salon. September 27, 2000:
Greg Stott of the Ontario Geological Survey points out the diamond occurences in Ontario

ABOVE: Greg Stott of the Ontario Geological Survey points out the diamond occurences in Ontario. The Ontario kimberlites erupted during early Jurassic times along the trend of dikes of diabase which were intruded during the Precambrian. More details available