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The faces of diamond octahedrons are highly lustrous owing to their hardness; triangular shaped growth defects (trigons) or etch pits are often present on the faces. A diamond's fracture is irregular. Diamonds which are nearly round, due to the formation of multiple steps on octahedral faces, are commonly coated in a gum-like skin (nyf). The ...
Main diamond producing countries. Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic.Diamond as a form of carbon is tasteless, odourless, strong, brittle solid, colourless in pure form, a poor conductor of electricity, and insoluble in water.
The high-pressure synthesis of diamond in 1953 in Sweden [21] [22] and in 1954 in the US, [23] made possible by the development of new apparatus and techniques, became a milestone in synthesis of artificial superhard materials. The synthesis clearly showed the potential of high-pressure applications for industrial purposes and stimulated ...
Diamond is the best natural conductor of heat; it even feels cold to the touch. Its thermal conductivity (2,200 W/m•K) is five times greater than the most conductive metal (Ag at 429); 300 times higher than the least conductive metal (Pu at 6.74); and nearly 4,000 times that of water (0.58) and 100,000 times that of air (0.0224). This high ...
The Chinese, who did not find diamonds in their country, initially did not use diamond as a jewel but used it as a "jade cutting knife". [12] Diamonds reached ancient Rome from India. [9] Diamonds were also discovered in 700 in Borneo, and were used by the traders of southeast Asia. [9]
The great expense of refining the metal made the small available quantity of pure aluminium more valuable than gold. [16] Bars of aluminium were exhibited at the Exposition Universelle of 1855 , [ 17 ] and Napoleon III 's most important guests were given aluminium cutlery, while those less worthy dined with mere silver. [ 16 ]
In diamonds, the cut is the primary determinant of value, followed by clarity and color. An ideally cut diamond will sparkle, to break down light into its constituent rainbow colors (dispersion), chop it up into bright little pieces (scintillation), and deliver it to the eye (brilliance).
Osmium is a hard but brittle metal that remains lustrous even at high temperatures. It has a very low compressibility. Correspondingly, its bulk modulus is extremely high, reported between 395 and 462 GPa, which rivals that of diamond (443 GPa). The hardness of osmium is moderately high at 4 GPa.