Diamonds and Carbon

By Bob Gariano

In the 1949 Broadway musical hit, Gentlemen Prefer Blondes, Carol Channing first performed one of the all time greatest American musical hit tunes, “Diamonds Are a Girl’s Best Friend”.

In 1953, when Marilyn Monroe was cast as heroine Lorelei Lee in the movie version of the play, she turned this hit song into a cultural icon of the twentieth century. In the movie’s plot, Lorelei is tracked by a detective hired by her fiancé’s father. The father suspects the young and beautiful Lorelei of being motivated to marry his son simply to access the family’s fortune. Lorelei’s nightclub rendition of the song placed her as one of America’s great musical actresses and is second only to her happy birthday song sung for President Kennedy as her most memorable performance.

The early chorus of the song includes the famous lines, “A kiss on the hand may be quite continental, but diamonds are a girl’s best friend.” I doubt if anyone associated with the production understood just how special diamonds are and how remarkable they are as one of nature’s rarest accomplishments. But the reality of this line still stands.

Basic Carbon

Diamond is a rare form of the basic element carbon, one of the four most common elements in the universe. Carbon is found as an element in all forms of organic molecules, that is, those molecules that make up living things. In its natural elemental state, carbon is presented in several very different forms or allotropes. These include graphite, which is opaque black, and diamond, which is transparent. Graphite is soft and can be used as a marking material. In contrast, diamond is one of the hardest materials known. Under normal conditions diamond is an electrical insulator, while graphite is a very good conductor of electrical energy. Conversely, diamond is one of the best thermal or heat conductors known.

Carbon has been known since antiquity and the word itself is from the Greek meaning coal. In its tetravalent structure, carbon can combine with a number of other common elements, especially hydrogen and oxygen, to form a dizzying array of so called organic compounds. It is this variability that accounts for the some of the diversity of life on planet earth. Scientists have identified more than ten million organic or carbon based compounds and this is a fraction of the number that could theoretically be formed using this versatile element as a backbone.

Inside Giant Stars

Every diamond is formed from carbon and all carbon was formed in a similar ancient reaction. Carbon is created when three alpha particles or helium nuclei collide almost simultaneously. The pressures and heat required for such triple collisions occur only in the cores of giant super stars.

Scientists believe that all the carbon in the universe originated in such cataclysmic events and that the resulting carbon dust was distributed into the universe when those giant stars eventually died in fiery explosions throughout the galaxies. The origination of elemental carbon in the cores of giant stars is only the first step in the natural production of diamonds. 

Making Diamonds

For all of the elemental carbon that is in the earth’s core, very little is converted into the form that we know as diamonds. For this to occur, the carbon must under go enormous heat and pressures. In the earth’s mantle, where diamonds form, the temperature of the super heated magma can reach over 1000 degrees centigrade. Pressures in this environment exceed 50 kilo bars. These unusual conditions only exist more than 100 miles below the earth’s surface.

Geologists estimate that much of this compression and heating occurred early in the earth’s existence. By dating radioactive inclusions in mined diamonds many of these precious stones have been shown to be more than three billion years old.

After they form in the earth’s interior, diamonds are still not at their journey’s end. Diamond, which appears so permanent, as in “diamonds are forever”, is not stable in the atmosphere at high temperatures. The normal, stable form of carbon is the much more pedestrian graphite or organic forms. To come to the surface as diamonds, the stones are transported at near supersonic sonic speeds inside of volcanic conduits called kimberlitic pipes. Slower emergence would allow the diamonds to degenerate as they came to the surface. The stones that we use as jewels today were all explosively transported to the surface inside of these pipes and then the gems are refined by man from the surrounding magma ore.

Special Places

Until the early eighteenth century almost all diamonds were found in alluvial deposits in India. In the middle of that century, similar deposits were found in Brazil and in the 1870’s major deposits near kimberlite eruptions were found in South Africa. Since the South African deposits were discovered, and careful records have been kept of production, more than 5 billion carats of gem and industrial natural diamonds have been mined throughout the world. Newer diamond mines today are located in Canada, Zimbabwe and Angola, though other smaller deposits of the diamond containing magma have been found in Russia and in the western United States.

The beauty and rarity of diamonds means that they are a sought after as precious adornments. On a sunny spring afternoon in Lake Forest, an alert observer can see many beautiful stones decorating the jewelry of sophisticated ladies. The journey that these precious gems took from the cores of exploding stars to the super heated magma inside the earth’s mantle to a super sonic conveyor to the earth’s surface should remind us of their scarcity. Even though the beauty of the stones will certainly out live the youth of the owners, there is something about diamonds that makes the wearer young again. It may be as the hit song says:

“Time rolls on and youth is gone and you can’t straighten up when you bend. But stiff back or stiff knees, you stand straight at Tiffany’s…Diamonds are a girl’s best friend.”

Bob Gariano is President of RGA, an executive search firm that recruits senior executives and board members for public and private companies. Bob can be reached at rgariano@robertgariano.com