Diamond's origin
Formation of Diamonds:
Diamonds form deep within the Earth’s mantle, not its crust.
The conditions needed are quite specific:
Depth
Typically, between 150 and 800 kilometers beneath the Earth’s surface.
Pressure and Temperature
The immense pressures (around 4 gigapascals) and high temperatures (near 1,000°C) force carbon atoms to arrange in a specific crystal structure, different from other forms of carbon, like graphite. This unique structure gives diamonds their characteristic hardness.
Misconception about Coal
Many people think diamonds form from coal. This is a misconception. The majority of diamonds formed long before the first plants (which eventually become coal after millions of years) appeared on Earth. Therefore, while both diamonds and coal are primarily carbon, their sources and formation processes are distinct.
The Journey to the Surface
For diamonds to be accessible to us, they need to travel from their formation depth to near the Earth’s surface. This is where kimberlite plays its role. Kimberlite magmas form deep in the Earth’s mantle and can erupt violently onto the Earth’s surface. As they travel upwards, they can capture diamonds and transport them to the surface. This is why diamonds are often found in kimberlite pipes.
Kimberley and the Diamond Rush
In the late 19th century, a massive diamond rush took place in South Africa, particularly in the town of Kimberley. Thousands of miners flocked to the region, digging the earth in hopes of finding diamonds. Their efforts resulted in the excavation of the “Big Hole”, one of the largest hand-dug excavations in the world. Over time, Kimberley became synonymous with diamonds and played a pivotal role in shaping the global diamond industry.
Importance of Kimberlite
While diamonds can be found in other types of rock, kimberlite is the primary source rock for diamonds. The reason why only some diamonds survive the journey to the surface is that the ascent of the magma is rapid and violent. If a diamond isn’t adequately protected within the kimberlite, it could burn up due to the intense heat or be destroyed in the turbulent journey.
In conclusion, the story of diamonds is a tale of deep time, immense pressure, and heat. It’s about Earth’s dynamics bringing these precious gems from the deep mantle to the surface and the human endeavor to extract them. The history and significance of Kimberley in this narrative serve as a testament to the allure and value we place on these sparkling stones.
Diamonds are harvested through several methods, each with its own characteristics:
Open-pit Mining: This is the most cost-effective method but has depth limitations. It involves creating a large pit or excavation in the earth’s surface to extract diamonds from shallow depths.
Traditional Underground Mining:
This method allows access to greater depths where diamonds can be found but is considerably more expensive due to the need for tunnels, safety measures, and specialized equipment.
Alluvial Mining:
Alluvial mining employs a large vacuum-like apparatus to extract sediments from riverbeds. This method is often used in regions where diamonds have been eroded from their original sources and carried downstream.
Offshore Mining:
Similar to alluvial mining, offshore mining occurs at sea, necessitating the retrieval of sediments from greater depths. It can be a challenging and expensive process due to the harsh marine environment.
After the sediments and materials are gathered, they are transported to processing factories. At these facilities, the diamonds are separated from the surrounding earth and rocks. It’s worth noting that for every 1 carat of diamond recovered, a substantial amount of one cubic meter of earth or rock must be extracted, highlighting the rarity and value of diamonds.
Once recovered, the diamonds are categorized and typically sold to wholesalers specializing in rough diamonds. These wholesalers, in turn, supply manufacturers with the raw material they need. Manufacturers operate diamond cutting facilities where skilled artisans cut and shape the rough diamonds into polished gemstones. Finally, the polished diamonds are sold to wholesalers specializing in cut diamonds, eventually making their way to retailers and consumers. This intricate process ensures that diamonds are sourced, processed, and distributed with great care and precision in the global diamond industry.
4C
What determines the value of a diamond?
Internationally, the 4C system is employed. Each “C” (in English) determines a factor that will have an impact on the price.
The 4C system, which stands for Carat, Color, Clarity, and Cut, is a globally recognized method for assessing the quality and value of diamonds. Each of these four factors plays a crucial role in determining a diamond’s overall worth and appearance:
1.Carat (Weight)
Diamonds are weighed in carats, with 1 carat equal to 0.2 grams. Larger diamonds are more valuable, and a 2-carat diamond is worth more than twice as much as a 1-carat diamond. It's important to note that carat for diamonds measures weight, while carat for gold measures purity.
2. Color
The best diamond is one that is completely colorless, although it's often referred to as "white." Color is graded alphabetically, with D representing the highest quality (totally colorless), and the lower end of the scale is not specified. Distinguishing between a D and an E color diamond typically requires an expert gemologist.
3. Clarity
Clarity refers to the presence of internal or external imperfections, known as inclusions and blemishes. A diamond with no detectable impurities at 10x magnification is considered pure. The categories range from FL and IF (completely pure) to VVS1, VVS2, VS1, VS2, SI1, and SI2 for diamonds with inclusions not visible to the naked eye. Inclusions visible without a loupe are categorized as I1, I2, I3 (or P1, P2, P3).
4. Cut
The cut of a diamond includes its shape and how well it has been cut. Different shapes have different prices, with the round brilliant cut being the most classic and expensive. There are also fancy shapes like pear, marquise, oval, and emerald. Some extremely fancy cuts include shapes like a Buddha, letters of the alphabet, or even a horse's head. The quality of the cut, including proportions and symmetry, affects a diamond's brilliance and, consequently, its value. Poorly cut diamonds will have less sparkle and be less valuable.
Graduation Reports
As diamonds are a relatively expensive material known only to certain specialists, businesses have been established to provide graduation reports, often referred to as ‘certificates.’ There are over a hundred such companies worldwide that issue graduation reports. Since these reports are merely opinions, they do not hold any legal weight. However, over the past few decades, some laboratories have proven to be highly reputable. Among professionals, reports from GIA (Gemmological Institute of America), HRD (Hoge Raad voor Diamant), and IGI (International Gemmological Institute) are commonly used.
GIA
(Gemmological Institute of America):
HRD
(Hoge Raad voor Diamant)
HRD is a Belgian-based diamond grading institution. Their reports are trusted in the industry and are often associated with European markets.
IGI
(International Gemmological Institute)
IGI is an international organization that provides diamond and gemstone grading reports. They are known for their global presence and certifications.
It’s essential for anyone involved in the diamond trade, whether they are buying or selling, to rely on these reputable organizations’ reports to ensure transparency and confidence in the diamond’s quality and value. These reports help establish trust in a market where the value of diamonds can vary significantly based on their characteristics.