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Carbonado, commonly known as black diamond, is one of the toughest forms of natural diamond. It is an impure, high-density, micro-porous form of polycrystalline diamond consisting of diamond, graphite , and amorphous carbon , with minor crystalline precipitates filling pores and occasional reduced metal inclusions. [ 1 ]
The Gobi Desert is the fastest expanding desert on Earth, as it transforms over 3,600 square kilometres (1,400 square miles) of grassland into wasteland annually. [58] Although the Gobi Desert itself is still a distance away from Beijing, reports from field studies state there are large sand dunes forming only 70 km (43.5 mi) outside the city.
The Sahara Desert is the major source of mineral dust [2], which subsequently spreads across the Mediterranean (where it is the origin of rain dust) and Caribbean seas into northern South America, Central America, and eastern North America, and Europe. Additionally, it plays a significant role in the nutrient inflow to the Amazon rainforest. [3]
The Gobi is overall a cold desert, with frost and occasionally snow occurring on its dunes. Besides being quite far north, it is also located on a plateau roughly 910–1,520 m (2,990–4,990 ft) above sea level, which contributes to its low temperatures. An average of about 194 mm (7.6 in) of rain falls annually in the Gobi.
The Gobi Desert as a whole was known only very imperfectly to outsiders, as information was confined to observations by individual travelers engaging in their respective itineraries across the desert. Among the European and American explorers who contributed to the understanding of the Gobi, the most important were the following: [7]
The weight would make it the largest diamond found in 119 years and the second-largest ever dug out of a mine after the Cullinan Diamond that was discovered in South Africa in 1905. The famous ...
A 2,492-carat diamond was unearthed at Botswana's famed Karowe mine this week by Canada's Lucara Diamond, one of the largest stones ever.. Lucara Diamond, in a news release Wednesday, said the ...
The metal would have been found in nature without the need for smelting, and shaped into the desired form using hot and cold hammering without chemical alteration or alloying. As of 1999, "no one has found evidence that points to the use of melting, smelting and casting in prehistoric eastern North America." [3] (p 136)