Most are found in kimberlites, which are pipe-like formations created as a result of volcanic and tectonic activity. The second geological source for diamonds is placer deposits. The diamonds are easily weathered out of their kimberlite host rock and are washed away by streams and rivers.
Surface searching consists of walking up and down the rows of dirt looking for diamonds lying on top of the ground. This is the most productive method following a hard rain. Rain washes the soil away, leaving diamonds and other rocks and minerals exposed on the surface.
Most diamonds are found in kimberlite pipes, and few pipes yield enough diamonds to be worth the effort of mining them. In fact, significant diamond deposits are so rare that many explorers are giving up.
Diamond occurs naturally but is extremely rare compared to other minerals. Diamond is thought to form 150 km to 200 km below the Earth's surface, where high temperatures (1050°C - 1200°C) and pressures (45 kilobars - 55 kilobars) allow it to crystallise.
Dimonds in Australia
Australia's largest and most economic diamond deposit has been the Argyle Mine, in the East Kimberley region of Western Australia. It started production in the early 1980s and was, for some years, the world's largest diamond mine by volume.
diamond, a mineral composed of pure carbon. It is the hardest naturally occurring substance known; it is also the most popular gemstone. Because of their extreme hardness, diamonds have a number of important industrial applications.
Diamond is only formed at high pressures. It is found in kimberlite, an ultrabasic volcanic rock formed very deep in the Earth's crust.
Natural diamonds typically form 150–200 km below the surface of the earth. Diamond formation does not occur everywhere at these depths, but only below the oldest continents that have been stable for billions of years; these areas are known as cratons (see figure 2 in Summer 2018 Diamonds from the Deep).
At the Crater, diamonds are often found loose in the soil, having been released during the rapid weathering of this unstable mantle rock. The original host rocks, described from Africa and other sites around the world, including those of the Crater of Diamonds were first described as kimberlite and peridotite.
A raw uncut diamond is a stone that has not been cut or polished by a professional and has no specific shape or size. Their quality is relatively high after mining, but they must be cut and polished to be used in jewellery. Raw uncut diamonds tend to have a brown or yellowish tint to a high degree.
Real diamonds sparkle differently from fakes, but without experience it's difficult to recognize the differences. A well-cut diamond will have a good mix of white light, called brilliance, and flashes of color, called dispersion. Diamonds also display a strong contrast of light and dark areas.
The chances of finding a diamond are 1 in 10,000,000. The chances of finding a diamond over 8 mm, in excess of 2 grams in weight are 1 in 1,000,000,000. That is one chance in a billion! OK, so you think you beat the odds and actually found a rough diamond.
One of the only places in the world where the public can search for real diamonds in their original volcanic source, Crater of Diamonds is a one-of-a-kind experience that brings people from all over the world to Murfreesboro, Arkansas.
Finding Diamonds in Rivers, Creeks and Streams
Rocks and minerals are often discovered along channels of water. If you are ever metal detecting along rivers, creeks and streams that are close to volcanic crater areas where there are kimberlites it is quite possible you may find a rock with a diamond.
Diamond production has increased 100 fold annually from less than 2 million carats earlier last century to more than 180 million carats today. Throughout that period, clever marketers have kept telling the story about the world running out of diamonds.
Most people know that natural diamonds are found deep beneath the Earth's surface. Mines are created to recover these magnificent artifacts, sometimes so large they can be seen from space. What may come as somewhat of a surprise though, is the fact that diamonds can be found beneath the ocean as well!
In this raw form, rough diamonds usually look like lumps of pale, colored glass. Although colorless or near colorless diamonds are a standard for cut, faceted, and polished diamonds, rough diamonds often carry some hints of color.
Diamonds have an isometric crystal structure, a specific gravity of 3.1–3.5, a Mohs hardness of 10, cling to a grease table, and glow under shortwave ultraviolet light in some situations. A combination of these traits is used to correctly identify an uncut rough diamond.
Most are found in kimberlites, which are pipe-like formations created as a result of volcanic and tectonic activity. The second geological source for diamonds is placer deposits. The diamonds are easily weathered out of their kimberlite host rock and are washed away by streams and rivers.
Painite : Not just the rarest gemstone, but also the rarest mineral on earth, Painite holds the Guinness World Record for it. After its discovery in the year 1951, there existed only 2 specimens of Painite for the next many decades. By the year 2004, there were less than 2 dozens known gemstones.
The average concentration of gold in Earth's crust is 'very, very low,' at 4 parts per billion. In its elemental form, gold is significantly rarer than diamonds.
Red diamonds are the rarest of the colored diamonds, with only 20-30 existing in the entire world. They get their beautiful red color from a rare process during their formation, which changes the crystal structure of the diamond and causes light to pass through it differently than colorless diamonds.