Diamonds are specifically renowned as a material with superlative physical qualities — they make excellent abrasives because they can be scratched only by other diamonds, Borazon, ultrahard fullerite, or aggregated diamond nanorods, which also means they hold a polish extremely well and retain their lustre.
The name diamond derives from the ancient Greek adamas (αδάμας; “invincible”). They have been treasured as gemstones since their use as religious icons in ancient India and usage in engraving tools also dates to early human history.
Diamond is the hardest natural material known to man: Its hardness set to 10 (hardest) on Mohs scale of mineral hardness and having an absolute hardness value of between 90, 167, and 231 gigapascals in various tests. Diamond's hardness has been known since antiquity, and is the source of its name.
The formation of natural diamond requires very specific conditions. Diamond formation requires exposure of carbon-bearing materials to high pressure, ranging approximately between 45 and 60 kilobars, but at a comparatively low temperature range between approximately 1652–2372 °F (900–1300 °C). These conditions are known to be met in two places on Earth; in the lithospheric mantle below relatively stable continental plates, and at the site of a meteorite strike.
Diamonds can occur in nearly any color, though yellow and brown are by far the most common. "Black" diamonds are not truly black, but rather contain numerous dark inclusions that give the gems their dark appearance. Colored diamonds contain impurities or structural defects that cause the coloration, while pure or nearly pure diamonds are transparent and colorless. Most diamond impurities replace a carbon atom in the crystal lattice, known as a carbon flaw. The most common impurity, nitrogen, causes a slight to intense yellow coloration depending upon the type and concentration of nitrogen present. The Gemological Institute of America (GIA) classifies low saturation yellow and brown diamonds as diamonds in the normal color range, and applies a grading scale from 'D' (colorless) to 'Z' (light yellow).
The blue hue was a result of trace amounts of boron in the stone's crystal structure.
Cut actually refers to two aspects of a diamond. The first is its shape (round, marquise, etc) the second is how well the cutting has been executed.
A diamond's cut will most certainly influence its fire (the lovely rainbow colors that flash from within) and brilliance (the liveliness and sparkle), as well as its perceived size and even, to some degree its apparent color. Different cuts reflect light in different angles. A diamond must be cut in a geometrically precise manner to maximize its brilliance.
The one thing everyone agrees on, geologists and diamond users alike, is that diamonds are the hardest and one of the most valuable substances man has ever known. Not only are diamonds used in jewelry (about 20% of all the diamonds mined), but they are more widely used in industry, to cut very hard metal, as tips of drill bits in mining, for record player needles, and for transistors and other electronic equipment.
South Africa produces about 80% of the world's diamonds, followed by Russia and South America. The diamond fields of South Africa were discovered in 1866 when a farmer's children found "a pretty pebble" in a river bed, a pebble that turned out to be a diamond worth $2,500!
Although man-made diamonds are produced today (by compressing carbon under intense heat and pressure), these are mostly for industrial uses and are smaller in size than a grain of salt. Man-made diamonds of a size needed for jewelry would cost more to produce than the cost of locating and mining natural diamonds of the same size.
The largest diamond ever found is the Odlinan diamond, now part of the British crown jewels, which weighed 3,106 carats when mined!
|Colorless||Near Colorless||Faint Yellow||Very Light Yellow||Light Yellow|
DIAMOND CLARITY SCALE
Very Very Slightly
FL (Flawless) - IF (Internally Flawless)
Flawless Diamonds reveal no flaws on the surface or internally are the rarest and most beautiful gems.
Internally Flawless Diamonds reveal no inclusions and only insignificant blemishes on the surface under 10x magnification.
VVS1 - VVS2 (Very, Very Slightly Included)
Very difficult to see inclusions under 10x magnification. These are excellent quality diamonds.
VS1 - VS2 (Very Slightly Included)
Only looking through a 10X loupe can pinpoint the inclusions in this category and are nearly impossible to see with the naked eye. These are less expensive than the VVS1 or VVS2 grades.
SI1 - SI3 (Slightly Included)
Diamonds with inclusions easily identified under 10x magnification. Finding flaws in this category with the naked eye is difficult. The gems in this category maintain their integrity, depending on the location of the inclusions.
I1 - I3 (Included)
Diamonds with inclusions which may or may not be easily seen by the naked eye. The flaws on the stones in this category will have some effect on the brilliance of your diamond.