Beauty Article

Diamonds are made up entirely of carbon. Pressure (diamonds can’t form above 100 miles below the earths crust) and temperature (750+ degrees F) are the factors that “change” the diamond from mere carbon into a treasured commodity. After millions of years undergoing this pressure and heat
the rough stones are settled in diamond-bearing rock and from there
wait for a volcanic eruption to bring them to the surface.
Diamond Mining Techniques

Pipe Mining: Primary Source-refers to the process of diamonds emerging to the earth’s surface in host rocks through volcanic pipes
which are pathways between the earth’s mantle and surface.

When an eruption occurs
other materials are carried up along with the magma
or lava. If the eruption originates far enough down in the earths surface
it could contain diamond-bearing rock
usually kimberlite or lamproite.

These eruptions must be extremely forceful and move at high speeds
for if the diamonds remain in the magna for a long period of time
they could burn up if the temperatures or turn to graphite.

From here
they conduct a process called open mining where the surface remnants are inspected for diamonds. Once those are exhausted
large shafts are plunged into the ground next to the volcanic pipes and more diamond-bearing rock is recovered
and taken to a screening plant where the soil is separated from the diamonds.

Diamond Mining
Alluvial Mining: Secondary Source- Refers to the removal of rough diamonds that have been relocated to oceans and riverbeds through erosion.

After an eruption occurs
some of the diamond bearing rock is displaced
often settling in ocean beaches and river beds. To extract this valuable substance
a process of Alluvial Mining is conducted. In order to remove the rock from these areas
the water must be pushed aside to get to the floor of the ocean or river. Usually a wall of mud and stone is constructed. From there
the miners using bulldozers or pumps bring the rock to the surface. It is then taken to a screening plant where the soil and silt can be separated from the rough diamonds.
Rough Diamond Quality

After the rough diamonds are mined
less than 20% are gem-quality
the other 80% have other uses. If not gem–quality
they fall into one of two other categories Near Gem-Quality or Industrial use diamonds.

Gem Quality: Approximately 20% of diamonds mined fall into this category. These are high enough in quality to be used in diamond jewelry. They range in clarity from Flawless to Visible Inclusions.

Near Gem Quality: These fall in a category between gem quality and industrial
so they need to be individually evaluated to determine if they could be used in jewelry in some way or if the quality is just to poor they are used in industrial ways.
They range in clarity from Visible Inclusions to industrial quality.

Industrial Quality: These diamonds are badly included stones and are functional only for industrial use; for example drills and saws or earthmoving equipment. These are categorized as industrial quality clarity.
Mining Facts

* Orapa diamond mine largest diamond mine-located in Bostwana
Africa
* Diamonds are a world wide source
mines are found in 25 countries and on all continents except Antarctica.
* Antarctica is thought to have an abundance of diamonds to be mined
but international accords prohibit mining there
* While America is the largest purchaser of diamonds than any other country
the US has only one diamond mine
located in Arkansas
* At least 200 tons of ore needs to be extracted and processed to product a single one carat gem quality diamond
* Only 20% of diamonds mined are gem quality stones


Sources:
http://www.howstuffworks.com/diamond.htm
http://www.costellos.com.au/diamonds/mining.html
http://americanradioworks.publicradio.org/features/diamonds/facts.html