Formation of Diamonds

Capture the Essence! of Scintillating Diamonds with this dazzling 2-carat Diamond Engagement Ring. Photo ©2015 EraGem Jewelry.   The formation of diamonds is a study in fascination. A diamond's epic adventure begins within the melting pot of the earth, the mantle. At a depth of between 90 and 120 miles, a mixture of elements roils at temperatures as high as 2,000 degrees Fahrenheit {5}.

Diamonds Require Heat & Pressure

The weight of the atmosphere, gravity, and the earth itself, which presses down upon this elemental mixture, measures between 45 and 60 kilobars (638-870 psi) {5}. In comparison, at sea level, the amount of pressure exerted upon the human body is 14.5 pounds per square inch (psi) {4}. Even the most highly trained scuba divers are limited to a depth of 165 feet below the sea. At this depth, with the sea and the atmosphere pressing down upon her, a diver will experience the force of 72.5 psi {4}. Seems like feathers compared to the pressure under which diamonds are formed. It is precisely because of this heat and pressure that diamonds are one of the most unique gemstones on the earth. What makes them so unique is that they are the only single-element gemstone known to man. The rarest and most valuable diamonds (D Flawless) are 100% carbon. Miraculously, within this roiling pot of bubbling elements, the carbon elements find each other and cling with all their might.

A Powerful Bond

It takes five carbon atoms to begin the process of diamond crystallization. Under these unique pressure and heat conditions, the electrons in these carbon atoms are able to form powerful covalent bonds {2}. It is these powerful bonds, which grow as billions of single carbon atoms continue joining to one another at points of four, that make diamonds so dense, so durable, so indomitable {2}. And it is their purity that makes them so scintillating, so delectable, so ravishing in their beauty.

A Rainbow of Diamonds

Even those which have been intruded upon by trace elements are among the most dazzling of nature's perfect gifts.  Fancy Colored Diamonds, as the GIA categorizes them, are the tantalizing colorful wonders that have captivated the attention of the world's most illustrious collectors. This rainbow of diamonds is the result of either deformation or intrusion in the crystal lattice. Red diamonds are believed to be the result of a deformation which creates an absorption band within the stone which restricts certain colors of the spectrum, releasing primarily red light to the eye {8}. Orange diamonds are intruded upon by elements. Just which elements are intruding is up for debate. It has widely been believed that nitrogen is responsible for the pumpkin-colored hues, but more recently hydrogen has become a suspect, as well. Yellow diamonds are the result of a greater concentration of nitrogen atoms scattered throughout the crystal structure. Green diamonds are among the rarest of the rare. It is bombardment of neutrons, gamma rays, and beta rays that creates their verdant hues {7}. Some of these diamonds have been only lightly irradiated, making their color fleeting {6, 7}. Polishing or faceting can lift this green sheen right of the stone {7}. However, when a diamond has undergone a steady battering of radiation, its color will rise from within, emerging intact through the cutting and polishing process {7}. Blue diamonds are intruded upon by trace amounts of boron {5}. Purple diamonds are the result of a defect similar to that found in red diamonds, though purples have two absorption bands instead of just one {1}. With so many nuances to the perfection of a diamond, it is no wonder that these glittering stones have become an objection of wonder, delight, and absolute fascination. ~Angela Magnotti Andrews, Staff Writer

References

1. Harlow, George E. The Nature of Diamonds. Cambridge University Press, 1998.
2. King, Hobart. "How Do Diamonds Form?" Geology.com. Accessed March 30, 2015.
3. Linberry, Cate. "Diamonds Unearthed," Smithsonian Magazine, December 2006.
4. National Ocean Service. "How does pressure change with ocean depth?" Accessed March 30, 2015.
5. Nature.Berkeley.edu. "Diamonds and Diamond Simulants." Accessed March 30, 2015.
6. Naturally Colored. "How do Colored Diamonds get Their Color?" Accessed March 30, 2015.
7. Rachminov Diamonds 1891. "What Makes a Diamond Green?" Accessed March 30, 2015.
8. Rachminov Diamonds 1891. "What Makes a Diamond Red?" Accessed March 30, 2015.