Diamonds: How Do They Form?
By Ashley Bailey , Thursday, November 16, 2006
If you look at the chemistry of diamond, it is pure carbon. The different arrangement of the carbon atoms makes it a unique gem. Diamonds have been considered precious since ancient times and is popular for their strength, hardness and purity. But only in the hands of a master diamond cutter does a diamond's sheer beauty become apparent.
How a diamond is formed?
Diamonds were formed in the earth thousands of years ago under extreme heat and pressure. This extreme heat and pressure in the earth transformed the carbon into crystals and turned it colorless. Although diamonds formed deep in the earth, volcanic activity is what brought them to the surface. Hence, these volcanic pipes have diamonds in them. Over time, as some other minerals mix with carbon the diamond may takes on color. Most diamonds have some hint of yellow or brown in them. Others that did not mix with minerals are colorless. Some diamonds undergo dramatic changes to vivid or unique colors. These are very rare and valued more than normal diamonds.
Where are diamonds mined?
Alluvial deposits on riverbanks in India, and then Brazil, were mined to supply Europe through the 1700s. Alluvial diamonds were found in Africa in the late 1800s. An alluvial deposit is a buildup of alluvium, or sediment. Diamonds in volcanic pipes were first located in Kimberley South Africa in 1869. Over the next century thousands of thus-named “kimberlite” pipes were developed in Africa and Russia. In 1976 a diamond-bearing lamproite pipe was found in Australia (the Argyle mine) and in the 1990s the Ekati kimberlite was found under a Canadian lake, which has led to the location of other diamondiferous fields in Canada. Today the most significant diamond producers are Africa, Russia, Australia and Canada. Asia and South America are also commercially important. Alluvial diamonds are mined in riverbed, coastal and deep sea operations and hard rock diamonds are mined using an open pit or underground process.
How diamonds are priced?
Diamonds are valued by their Cut, Color, Clarity, and Carat weight. You should remember the C's that are used to value diamonds. Cut, Color, and Clarity are used to measure the quality of the diamond and the final C, which is Carat, is used to measure the size of the diamond. Man creates cut in a diamond and the other C's are formed in nature. Smart shoppers will also keep another C in mind: Confirmation, which depends on what the manufacturer and seller offer.
What types of diamonds are there?
When minerals mix with diamond in nature, it gives the diamond color. Based on the type of mineral that is mixed, we can classify the diamonds. The following are colors that are found.
- Yellow: this color is formed when Nitrogen combines with diamond crystals.
- Brown: Dislocation in the lattice of atoms causes brown coloring.
- Blue: During the formation of the diamond if elements of Boron are mixed then the diamond may take on blue coloring.
- Green: Green is caused due to a missing atom in the lattice of atoms.
- Pink: Dislocations in the lattice, missing atoms and some impurities that are non-nitrogen cause pink color.
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