Natural Diamonds and where they form
what does it mean to be a natural diamond?
Natural is of course, something constructed in Nature. Diamond is pure, or nearly pure, crystallized Carbon in its hardest form. The Carbon atoms are structured in the form of four, interlocking, strong covalent bonds.
Typically all gemstones begin to form in the Earth's Crust. Natural Diamonds are exceptional. They form 90 to 120 miles below the Earth's Crust in a somewhat molten layer of the Upper Mantle. At this depth, the earth is both powerful and violent. Pressure and heat are extremely high for Diamonds to grow in. This is one good reason we Color and Clarity grade Diamonds. These conditions are controlled by nature and nothing more. Most Natural Diamonds present numerous types of inclusions. This is generally what makes a Flawless, Colorless Diamond so rare. On the other hand, the variety of inclusions formed also serve as a Natural Diamonds fingerprint.
The best geographical regions of formation are located under large, extremely old, unchanging sections of landmass known as Cratons. There are none along the ocean floor. Peridotite, an igneous host rock that Natural Diamonds grow in, has an abundance of Carbon. Diamonds that have formed, remain underground until Kimberlite rocks find a fissure in the Earth and carry them up to the Crust through small volcanic eruptions. Kimberlite is an igneauos rock that gathers the Diamonds after they form in Peridotites. They are constantly making their way to the surface. There is nothing simple about the process. Consider timing, temperature, pressure conditions, and an exchange of materials; It becomes even more difficult for a Diamond to reach the surface. Add the fact that very few Kimberlite rocks contain Diamonds and you can understand why they are so precious.
Natural Diamond Mining
when diamonds reach the surface
Natural diamond deposits
Open-Pit Mining is performed at the Primary Deposit; once Natural Diamonds reach the Earth's Crust. This is the excavation of dirt and mineral bearing rock across a large surface area. Diamonds in a Primary Deposit are embedded in the Kimberlite rock that brought them up. From there, they descend through rivers and valleys, where they encounter Secondary Deposits. These Secondary Deposits are Alluvial and Marine Deposits. Alluvial Deposits are Natural Diamonds located in riverbeds and streams as they travel downward, toward the river's mouth. On the other hand, some Diamonds can linger in place for years, long after a riverbed has dried up. Marine Deposits crop up once the Diamonds have made their way off-shore. From there, the mining is done as divers and robotic crawlers vacuum up material off the ocean floor. Equipment for Diamond mining is very costly. The industrial machinery and technology used to mine are on a very high level. Natural Diamond mining also provides a way of life for many by providing jobs in many countries.
Sorting through diamond rough
The GIA international diamond grading system
After the Natural Diamonds are mined, they are then gathered and sold off to manufacturers in their rough (raw) state. Keep in mind, Natural Diamonds acquire a wide assortment of inclusions as they form. These inclusions can be colorless, translucent, or opaque. They affect the Clarity of the crystal. Nitrogen impurities and structural distortion are two typical causes of Color in Diamonds. It lends the Diamond Yellowish or Browish in color. Manufacturers have to take these things into account when they Cut a Diamond to achieve the most Carat weight and brilliance possible.
After the Diamond has been Cut, they are graded for quality by a laboratory. GIA established the International Diamond Grading System. This Grading System is not only widely used and accepted by other commercial laboratories, but dealers use GIA grades specifically to communicate quality between each other. GIA use the four main categories above to define a Diamond's quality. Those categories are Clarity, Color, Cut, and Carat. They are known as the Four C's of a Diamond.
The Four C's provide communication throughout the entire jewelry market. From the manufacturer to the customer, Diamonds are categorized by Price according to the combination of these four characteristics. The Grades are compared against U.S. and International markets. A global Diamond Pricing sheet is routinely released by Rapaport. It informs dealers of the current market pricing across the world. U.S. Pricing is researched and recorded by Gem World International as well. A Natural Diamond's price per Carat is on a constant incline. Meaning, the Diamond you are seeking out now will cost more in the future.