
Diamonds - Where They Come From
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.
Pipe 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.
Alluvial Mining
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
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.
The Four C's
What you "C" is what you get
The diamond is a true marvel of nature. Magical. Mysterious. Universally
treasured. And no two are exactly alike. Yet choosing a diamond you'll both love
is not so mysterious - when you understand the characteristics that distinguish
one gem from another. Any explanation of a diamond's beauty and value centers on
three key quality factors: cut, color and clarity, and one unit of measure:
carat weight. Collectively these are known as the four Cs. Learn what to look
for. Decide your priorities. Then make the choice that's right for you.
Cut
A diamond that is masterfully cut displays maximum brilliance and fire. Cut and
proportion are extremely important because they have the greatest influence on
the sparkle and value of a stone. A diamond that is well cut reflects light from
one facet to another and disperses it back through the top of the stone.
Color
A diamond's body color can range from totally colorless to light yellow. The
whiter or more colorless the stone, the more costly, because the absence of
color is more rare. Also, the less color in the stone, the easier it is for
light to pass through and be dispersed back into the spectrum of colors, like a
rainbow.
Clarity
Nature is rarely perfect. So it is very rare to find a diamond that is
completely pure or free of inclusions - minerals or crystals trapped within the
stone at the time it was formed. Without ten-power magnification, you may never
see these tiny inclusions. But they are the fingerprint that makes each diamond
unique.
Carat Weight
The size of a diamond is defined by its weight, which is expressed in carats.
One carat weighs one-fifth of a gram, and is divided into 100 points - like
pennies to a dollar. The larger the diamond the more rare and costly it is.
However, depending on their color, clarity and cut, two diamonds of the same
carat weight can vary widely in their value.
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