How are diamonds mined ?

The Ministry of Education and Science of the Russian Federation

FEDERAL STATE EDUCATIONAL INSTITUTION OF HIGHER EDUCATION

Russian State Geological Prospecting University

MGRI-RSGPU

“DIAMOND”

Marsel Balkhiev PG-15-4

Moscow 2015

Contents

• What is a Diamond-3

• How are diamonds Mined-3

• What is a “Synthetic” Diamond-4

• Chemical Vapor Deposition-5

• Diamond Simulants-5

• Cubiz Zirconia-5

• Moissanite-5

• Diamond and Graphite-6

• References-8

What is a Diamond?

Diamond is a native crystalline carbon that is the hardest known mineral. It is usually nearly colorless. When transparent and free from flaws it is highly valued as a precious stone. It is also used industrially, especially as an abrasive. Crystallized carbon produced artificially is also called diamond. The name diamond is derived from the ancient Greek adamas ("invincible"). Their hardness and high dispersion of light make diamonds useful for industrial applications and jewelry. Diamonds make excellent abrasives, because they can be scratched only by other diamonds, or man-made materials, which also means that they hold a polish extremely well and retain their lustre. They have been treasured as gemstones since their use as religious icons in ancient India. Thier usage in engraving tools also dates to early human history.The popularity of diamonds has risen since the 19th century because of increased supply, improved cutting and polishing techniques, growth in the world economy, and innovative and successful marketing campaigns. Gem diamonds are commonly judged by the “four Cs”: carat weight, clarity, color, and Cut. Approximately 130 million carats (26,000 kg) are mined annually, with a total value of nearly USD $9 billion, and about 100,000 kg of synthetic diamonds are manufactured annually. 49% of natural diamonds originate from central and southern Africa, although significant sources of the mineral have been discovered in Canada, India, Russia, Brazil, and Australia. They are mined from kimberlite and lamproite volcanic pipes, which brought to the surface the diamond crystals from deep in the Earth where the high pressure and temperature enables the formation of the crystals.

How are diamonds mined?

There are two basic types of mining used to bring these gems close to home: Pipe Mining and Alluvial Mining. Neither of these really fits the notion of workers in hard hats exploring cavern-like diamond mines, perhaps carrying a pick ax and whistling a song! Both methods require massive amounts of labor and planning in order to locate diamonds, however it is the latter of the two methods that started the world’s obsession with crystalized carbon. The term, Alluvial Mining is based from the Latin word of “Alluvius” – which roughly translated means “to wash against”. This provides a better understanding of the actual process of alluvial diamond mining which is done in riverbeds and beaches where diamonds have been washed out of their host rock and transported by erosion. At about the 9th Century BC to the mid-18th century AD, India was the primary source for diamonds which were procured by alluvial mining. This method requires that walls be built to hold back the water and sand in the area rich with diamonds – or as the case is now, beaches are moved by machinery until the deposits of diamonds can be easily found, though there’s nothing easy about moving tons of earth! Originally, the sand would have be sifted and examined in order to find the precious goods – now the sand is loaded and sent to a screening facility which scours the sand until diamonds are found. In a way, it brings the diamond mine to the workers instead of the other way around. As the desire and search for diamonds increased – people sought new ways to recover these gems which lead to the more widely known form of diamond extraction: Pipe Mining. Pipe Mining is done where diamonds have been located in situ, having come from deep in the earth through natural volcanic fissures/tunnels or “pipes”. While the volcanic pipes are natural, the tunnels used to extract the diamonds are calculated and man made. This provides the type of diamond mine we’ve come to know in various places around the world. In a way – these types of diamond mines allow for more predictable retrieval than alluvial mining. Instead of allowing diamonds to slowly creep their way along a volcanic pipe up to the surface of the earth to be swept away into a river or ocean bed – the diamonds are retrieved while they are ‘closer to home.’ This type of diamond mine allows searchers to break up the earth near the volcanic pipe and transport it to the surface, where once again it is transported to a screening facility to really hunt and find diamonds outside of the actual mining area. Diamond mining requires massive amounts of time and effort, and is very costly. The methods have improved in safety and efficiency over the years which allows for these rare valuables to become surprisingly accessible. Next time you see a diamond casually online or in a neighborhood store – remember that without the art of mining – we’d not have the opportunity to see these gems sparkle above the ground.