Diamond History and Qualities
Diamond origins and mining: recovering rare beauty
Its origins are pure carbon, not unlike the graphite in an ordinary pencil. But this carbon was turned into clear crystals – in fact, the hardest substance known to man – by tremendous heat and pressure deep within the Earth.
Diamonds are mined using two methods. The primary method is pipe mining; the secondary is alluvial mining.
Magmas containing diamonds generated by volcanic activity cooled to form diamondiferous cores or "pipes" in the earth. Pipe mining is similar to the process for mining coal underground: the "blueground" (a term used to describe the earth in which diamonds are formed) is crushed and flushed with water as it moves on conveyor belts through tubes. Once the diamond-bearing matter is washed, it is dropped onto greased belts. Diamonds stick to the grease; other matter is washed away. The grease is then boiled away, leaving rough diamonds.
In mining diamonds, it takes approximately 23 tons of blueground to yield 5 carats of rough diamond material. Furthermore, only 20% of any diamonds recovered are gem quality, while the remainder is suitable only for industrial purposes. Industrial-quality diamonds are used in drill bits, saw blades and in PC chip manufacturing, among other applications.
Some diamonds were released from volcanic pipes by erosion of the earth's surface, and were washed away down ancient riverbeds or to coastal areas. This action created alluvial deposits from which diamonds are recovered. To mine these deposits, huge bulldozers shovel the alluvial sands directly into washing plants for processing. Completely mechanized, this method is less costly than opencast pipe mining. Smaller operations also still exist in the rivers themselves where sediment is processed for diamond rough – often using techniques that have not changed in a hundred years.
Where diamonds are found
The earliest references to diamonds – dating perhaps as early as 2800 BC – occur in the Book of Exodus. They can be traced back to riverbed sources in India, based on the known routes of Arab traders. The volcanic source of these diamonds was never discovered, but the alluvial deposits were rich enough to supply most of the world's diamonds until the 18th century. At that time, dwindling Indian supplies likely spurred the exploration that led to the discovery of diamonds in Brazil, which became the next important diamond source.
The biggest diamond discovery in history occurred in 1866. This is when South Africa's massive diamond deposits along the Orange (Boynswaga) River were discovered, prompting a worldwide diamond rush. The South African diamond output was unrivaled until 1954 when major deposits were found in Siberia. Currently, Western Canada is the site of the world's newest diamond rush. Diamond deposits also can be found elsewhere in Africa, the United States, Australia and China.
Diamond cutting – advancing the art
There is a world of difference between the uncut diamond in the rough and the final polished, scintillating gemstone. The raw diamond may appear like a lump of molten glass that is coated with a translucent film. Uncovering the great beauty of a diamond depends on man's skill to take maximum advantage of the physical laws of optics. As old as the diamond cutter's trade is, it has taken a long time to learn how to cut a diamond so as to maximize its brilliance.
By the mid-1700s, the science of optics and the understanding of diamond cutting converged. The result was the development of the brilliant round cut, the most popular diamond cut to this day. The brilliant cut diamond represents the highest advances made in the art of diamond cutting, and brings out the most brilliance and fire from the diamond's natural properties. But there has continued to be some debate in how to simultaneously maximize brilliance, scintillation and dispersion (the diamond's sparkle and fire).
Enter a mathematical approach
In 1919, master gem cutter and mathematician Marcel Tolkowsky calculated a compromise: a perfectly symmetrical diamond cut with 58 facets and precisely dictated proportions. The most widely accepted proportions for diamonds cut today have evolved from Tolkowsky's model. However, since diamonds were first cleaved, there has been ongoing debate as to the "ideal" or "perfect" cut.
The diamond – in elemental terms
Transparent gems made of pure carbon, diamonds are the hardest, most enduring and most brilliant of all minerals. Not only are they extremely rare, but they possess remarkable physical qualities that cause them to be universally treasured:
- No two diamonds are exactly alike
- Diamonds are the hardest substance known to man. They register 10 on the Mohs scale of hardness, and are nearly 100 times more resistant to scratching than the next hardest substance
- Their hardness allows diamonds to be cut with precise accuracy to manage light
- The hardness allows diamonds to last forever
- While diamonds are harder than other substances, they are NOT unbreakable. Like a piece of grained wood, a diamond struck against the grain may crack, chip, split or even shatter
- Diamonds are not affected by changes in temperature, but they will burn at 1,444 degrees Fahrenheit
- A diamond's beauty comes from the light that passes through it, or is reflected from it. A properly cut diamond is like a prism, dispersing rays of light in all direction, and in all colors of the spectrum. This is the source of its fire.