Diamond is a colourless exceptionally hard mineral but often tinted yellow, orange, blue, brown, or black by impurities, located in sure igneous rocks esp. the kimberlites of Southern Africa. it is used like a gemstone, as anabrasive, and on the working edges of cutting tools. Crystal structure: cubic. structure of atom the Greek adamas meaning invincible.
Cleavage eminent along octahedral faces. Lustre brilliantly adamantine. Birefringence and pleochroism: none cubic. Diamond crystals shape as cubes, octahedra, the highest many common gem form, and dodecahedra. Colourless to yellow diamonds which hold a tough absorbtion line within the violet end regarding the spectrum are members regarding the Cape series.
Where is it found?The most well-known diamond bearing place is Southern Africa. First diamond was reported in 1866. 5 carat diamond had been located and was named The Star of Africa. It was subsequently slice into a pear shape brilliant weighing 47. The Golconda region of Southern South asia was the source of somefamous diamonds for example the Koh-i-nor hill of light 186cts slice to 108.
92 cts and now within the Tower of London and Jehangir. Diamond is widespread in Brazil, most stones being mini but of good gem quality. Alluvial diamonds have been located in most states regarding the USA. Clean and fancy coloured diamonds for example pinks and pinkish browns are mined at Argyle in North Western Australia. Other important producers are Russia, now the fourth largest producer, and China.
By mass the top ten producers in 1994 were: By Price The top ten were: Australia Botswana Zaire Russia Botswana Southern Africa Russia Zaire Southern Africa Australia Southern America Namibia Angola Angola Namibia Southern America Ghana Guinea Guinea Sierra Leone. Estimated 2001 Diamond Production by Place Country Carats 000 Price $ m Botswana 26,416 2,194 Russia 20,500 1,650 Southern Africa 11,301 1,145 Angola 5,871 803 D. Congo 19,637 496 Canada 3,685 531 Namibia 1,502 322 Australia 26,070 294 Guinea 754 128 Sierra Leone 375 68 Central Africa Republic 614 92 Venezuela 325 41 Tanzania 191 28 Brazil 550 22 Liberia 155 23 Ivory Coast 145 17 China 150 15 Ghana 450 11 Lesotho 20 5 Guyana 20 3 Total 110,176 7,253 Source: Mining Journal, London, August 23, 2002. Current Annual Production at World's Primary Mines, 2001. Carats Tonnes US$ or carat Price 000 000 $ m.
Ekati 3,685 3,685 144 531. Jwaneng 12,339 8,920 110 1,357 Orapa 13,056 15,779 50 653 Letlhakane 1,021 3,625 180 184. Venetia 4,977 4,602 85 423 Namaqualand 808 6,083 180 145 Finsch 2,465 4,768 70 173 Premier 1,637 3,102 75 123 Kimberley 550 3,766 110 61 Baken 65 5,835 400 26 Koffiefontein 145 2,299 225 33. Udachnaya 11,500 9,000 85 978 Jubilee 5,500 9,100 65 358. Argyle 26,000 15,100 11 286 Merlin 70 270 110 8.
Namdeb Onshore 1,385 21,867 220 305. Source: Mining Journal, London, August 23, 2002 How diamonds are formed?. Diamond is formed at good depth within the earth, between 150 and 300 km below the surface and at good temperatures and pressures. By a kind of volcanic eruption the diamonds were pushed up through volcanic pipes of diamond bearing rock for example kimberlite. With gradual erosion kimberlite chimneys were exposed at the earths surface.
No comments:
Post a Comment