How Diamonds are Made
It is a known fact that a diamond’s chemical composition is the same as the chemical composition of graphite or carbon. Even though people are aware of that fact, they have a difficult time believing it is true simply because the physical properties and outward appearance of a diamond is so much different from that of graphite. Anyone would be fascinated in how diamonds are created and how they reach accessible places. Naturally, diamonds are developed under extreme temperatures and pressure, miles beneath the surface of the Earth and are transported to the Earth’s crust with rocks. Long before diamonds can be worn as jewelry, they go through a process of discovery, exploration, cutting, and polishing so a person can fully see the natural shine a diamond has.
Scientists did not know how diamonds formed until late in the twentieth century. Chemists, gemologists, physicists, and mineralogists have combined their knowledge over the last fifty years to come up with everything we know about diamonds today. The formation of diamonds and how they are transported to the surface of the earth has led to the methodology in which various diamond sites are being predicted and explored today. The knowledge of how the stones are formed and transported also helps people appreciate their components and rarity. The conditions and methods required in their creation are rare and unique and even the slightest missing link would result in the stone not being a precious stone at all.
A French chemist, Antoine-Laurent Lavoisier, put a diamond in a chamber filled with oxygen. He then used a magnifying glass to focus sunlight on it. If he would have never done this, it is very likely that we would still not know what a diamond was made of. This experiment had astonishing results and although he expected to find ash in the bottom of a jar, the diamond vanished. It was then that he concluded that the diamond was made of carbon and the reason for its disappearance was because of carbon dioxide.
Smithson Tennant, a chemist from England, compared the amount of gas that was released from a diamond and charcoal of certain weights, and concluded that the weight of the gas was the same. In 1797 the results were published but it still took over two decades before people would be convinced that the chemical composition of charcoal and a diamond was the same. Graphite is made of carbon as well but if the physical properties were to be examined you would find that it is much different from the carbon found in diamonds and charcoal.
In order for diamonds to form, the temperature must range from
900 degrees Celsius to 1300 degrees Celsius. High pressure is measured
by a unit called a kilobar. The pressure must range from 45 kilobars
to 60 kilobars. Once scientists understood the pressure and
temperature required in order to form diamonds, they started studying
other rocks that came with diamonds to the earth’s surface. Because
there was enough knowledge of other rocks and what level they could be
found within the earth’s crust, scientists predicted that diamonds
formed around 90 up to 120 miles below the surface of the earth.
When other rocks found with diamonds were studied, it was found that they were eclogite and peridotite rocks which are igneous rocks. These rocks start off in a partially molten or molten state and harden when they cool as they come closer to the surface. This is why having an understanding of geology is important for any person wanting to find any diamond locations. The combination of pressure, mineral composition, and temperature required for formation and the carbon supplied by each during the process of forming will differ. This means the diamonds produced have different formations, inclusions, and crystal structures.
Diamonds are found in lamproite or kimberlite rocks on the surface of the earth. The rocks are similar in chemical composition and how they are carried to the earth’s surface is known as emplacement. It was believed that diamonds were produced by these rocks but once man discovered how to measure the age of a rock, the age of rocks that carried diamonds was lower than the actual diamonds themselves. Lamproite and kimberlite rocks get to the surface of the earth through a process known as convection currents. The earth’s heat helps in keeping the mantle molten and as it heats up, it moves to the surface and cools. Once cooled, it solidifies, becomes heavy, and descends again. As it lowers, it heats again. During upward movements it meets a fracture in the crust of the earth and continues its move to the surface. If the molten magna crosses paths with a diamond pouch along the way it will carry the diamonds to the earth’s surface as well. There are times when the diamonds will stay embedded in eclogite or peridotite rocks but other times the heat will cause rocks to dissolve which will leave diamonds free and loose allowing them to be retrieved easily.
The gushing of magna happens quickly and while the emerging mass of molten reduces, the speed is also increasing. Due to the speed and reduction in pressure, some magna becomes gas consisting of carbon dioxide and water vapor. This delivery speed and gases are essential in helping the diamonds survive and keep atomic bond without converting to graphite. The kimberlite or lamproite rock shoots out with force but does not gush like volcano lava and is a mixture of gases, solid rock, and ash. There have roughly been around 6000 emplacements which have occurred throughout the world and around 1000 of those actually contain diamonds. 50 of those are viable enough to mine but today only 20 of those are actually being mined.
After understanding what diamonds are composed of, how they are formed, how they are created, how they are transported and the conditions necessary for them to be available to humans, you can understand why they are held at such high value. A diamond being present close to the surface of earth is in itself a miracle and after it is retrieved it is cut, polished, and set into jewelry before it is in your hands. Knowing the miracle and technical details in these processes will put you in a better place to understand and appreciate a diamond’s pure glistening beauty.