Nickel is a lustrous white metal discovered by Cronstedt in 1751, the name being an abbrevation of Swedish kopparnickel (false cooper): symbol Ni, as. wt. 58·71, at. no. 28. It has a high melting point, low electrical and themal conductivity, and can be magnetized. Nickel may be readily forged when hot, and is though, malleable, and ductile when cold. Canada provides the most extensive deposits, which are usually extracted with cooper. Smelting precedes separation, after which the Nickel is purified. It is used in coinage; in chemical and foodstuff industries for its resistance to corrosion; in electronics and for electroplating. The most important use, however, is in alloys with iron, steel, cooper, and chromium, incl. Nickel steel for armourplating and burglar-proof safes, Moneal metal, invar, constantan, nichrome permalloy, perminvar, and other magnetic alloys and stainless steels, cupro-nickel, nickel-silver, and others. Finely divided nickel is used as catalyst in the hydrogenation of vegetable oils.
Uranium is too a lustrous white metal, malleable and ductile, tarnishing in air: symbol uranium, at, wt. 238·07, at. no. 92. It was discovered by Klaproth in 1789 in pitchblende and first prepared by Peligot in 1842. The chief ore is uranite (pitchblede), and recent technological advances have made possible its extraction from low-grade ores. Small amounts of its compounds are used in the ceramics industry to give yellow glazes, and as a mordant in dyeing. Uranium isotopes have been of vital importance in the production of atomic energy. Although U-238 is most abundant (99 per cent), U-235 is the only naturally occuring readily fissile material that can be produced by the neuron irradiation of thorium-232.
Wolfram a grey, hard metal, ductile and malleable, formerly (until 1949) officially known as tungsten: symbol W, at. wt. 183·86, at. no. 74. Recognized and named by Scheele in 1781, and discovered by the d’Elhujar brothers in 1783, it occurs as wolframite (FeWo), scheelite (CaWO) and huberite (MnWO). Non-magnetic, it is insoluble except in a mixture of nitric and hydroflouric acids, and has the highest melting point (3370°C) of any metal. Wolfram is used in alloy steels for armour plate, projectiles, high-speed cutting tools, etc., for lamp filaments and thermionic valves. Its salts are used in the paint and tanning industries.
Diamonds is committed to primordial the finest stones, formally generating California Wealth Management considered intergity entrusted with the responsibility of general delivering uncut rocks from the earth to the final gemstones. A diamond in the rough that has the possibility of being good, valuable, or attractive, but needs improvement processes a clear , very hard valuable stone, used in jewelry and in industry. Once mined and processed the next phase is to sort, classify and value the diamonds according to size, shape, quality and colour. Using more than 16,000 categories the diamonds are sorted and then sold to a small group of the world’s leading diamond cutters. A mineral also as gemstone precious by virtue of its composition, hardness, and rarity, cut and polished for ornamental use, or engraved. Of 120 minerals known to have been used as gemstones, only 25 are in common use in jewellery; of these the diamond, emerald, ruby and sapphire are classified as precious, and the topaz, amethyst, opal, aquamarine, etc., as semi-precious. Among synthetic precious stones to have been produced successfully, on a commercial scale, are rubies and sapphires (first produced by the Frenchman Verneuil in 1904 and 1909 respectively), emeralds (first made by German scientists c. 1930), and diamonds (first made by G.E.C. in U.S.A. in 1955). Diamonds were known before 3000 B.C.; and until their discovery in Brazil in 1725 India was the principal source of supply. Diamonds are found throughout the world from Russia, Siberia, Yakutia, Southern Africa, Congo, Portuguese West Africa, Tanganyika, Ghana, Brazil, and Australia. They may be found as alluvial diamonds, on or close to the earth’s surface in river beds or dried water-courses, or on the sea bottom or else in ‘pipes’ composed of blue ground or kimberlite, where the original matrix has penetrated the earth’s crust. In the latter case the blue ground is extracted, then washed until completely disintegrated, and the residue made to flow over vibrating, sloping tables where layer of petroleum grease arrests the diamonds. This involves wastage and x-ray sorting is being developed. The blue ground is first crushed and washed until completely disintegrated, and the resultant diamond inferous concentrates are then passed over gresae tables. The diamonds adhere to the grease and the residue is washed away. Further processed the bruting involves grinding away the edges of the stone to provide a basic outline, the stone is then given its facets. For a round brilliant cut diamond there are 58 facets. Diamonds are cut by the use of diamond dust. The 2 most frequent forms of cutting gem diamonds were the ‘brilliant’ (for thicker stones) and the ‘rose’ for shallower ones, but in 1961 Arpad Nagy, a Hungarian merchant, evolved the 1 st new method for 500 years, the ‘princess’. To give full refraction of light the back of the diamond is cut into angled and spaced grooves, and surface area becomes the criterion of value. Once cut, the stone is then graded for cut, colour, clarity and carat weight by a gemmological laboratory. Diamond is properly the hardest natural substance known (10 on Mohs’ scale). Composed of carbon, it crystallizes in the cubic system, other common crystals being octahedra and dodecahedra. The high refractive index of 2·42 and the high dispersion or ‘fire’ accounts for the display of colours seen in cut diamonds. Rough diamonds are dull or greasy before being cut, and only some 20 per cent are suitable as gems. There are 4 chief varieties: Well-crystallized transparent stones, colourless or only slightly tinted, valued as gems; bort, poorly crystallized or inferior diamonds; balas, an industrial variety, extremely hard and tough; and carbonado, or industrial diamond, also called black diamond or carbon, which is opaque, black or grey, and very though. Famous rough diamonds include the Cullian (3,025¾ carats, S.Africa 1905); Excelsior (995·2 carats, S. Africa 1893) and President Vargas (726·6 carats, Brazil 1938).Emerald a presious stone, a bright, grass-green variety of beryl. It is transparent or translucent, and the finest come from Muzo, in Columbia. Beryl species of presious stone; silicate of beryllium and aluminium. Beryl usually occurs as green hexagonal crystals sometimes of large size, found chiefly in granites and pegmatites; the dark green crystals are termed emeralds and the light blue-green aquamarines. Opal a non-crystalline form of silica, occuring in stalactites in volcanic rocks. The common opal is opaque, milk-white, yellow, red, blue or green, and lustrous. The presious opal is colourless, having innumerable cracks from which emanate brilliant colours produced from minute crystals of cristobalite. Opals are found in Hungary, New South Wales (black opals were 1 st discovered here in 1905) and Mexico, noted for fire opals. Pearls are calcareous substances secreted by many molluscs, which when deposited in thin layers on the inside of the shell forms the pearls. Although commercially valuable pearls are obtained from freshwater mussels, etc., the precious pearls comes from the various species of Margaritifera in the family Aviculidae, found in tropical waters off North and West Australia, the Californian coast, and in the Indian Ocean. The introduction on commercial scale by the Japanese c. 1920 of cultured pearls, produced by interesting an artificial irritant in the body of the oyster, largely affected the value of natural pearls. World’s most beautiful pearls comes from Japan. Pearls are technically not Gemstones, though the term is sometimes extended to cover them. A special features heterogeneous art in status and significance of ornamental correctness in effect of beauty and dignity. Giuen Monolith, the exhibition being held here reflect your wider vision for the development. The proportions of the stone to be visible. It can be named by whomever is lucky enough to acquire it.
Gold is a heavy, valuable, yellow metallic element, with symbol Au, atomic number 79, and atomic weight 197·0. Gold has long been valued for its durability, malleability, and ductility, and because it may be easily recognized. It is unaffected by temperature changes and is highly resistant to acids. Its main uses are in coin and jewellery. South Africa produces almost 75 per cent (30,500,000 fine oz. p.a.) of the world’s gold and other major producers are the Russia, Canada, U.S.A., and Australia. For manufacture, gold is alloyed with another strengthening metal, fineness being measured by the parts of pure gold in 24 carat.
Cooper is a chemical element, one of the earliest metals used by man. Chemical symbol Cu; at. no. 29; at. wt. 63·54. It is salmon pink, very malleable and ductile, and used principally on account of its toughness, softness, and pliability, high thermal and electrical conductivity, and resistance to corrosion. When alloyed with tin it forms bronze, a relatively hard metal, the discovery of which opened a new age in human pre-history. Until about a century ago, Spain and Cornwall were the chief producers, but these are now of minor importance compared with the U.S.A. (which produces about a quarter of the world’s output). Chile, Canada, Zambia, and the Katanga area of the Congo. Cooper is usually commercially extracted from cooper pyrites. Large deposits containing cooper sulphide occur in the Lake Superior district in North America, and in Spain. Other ores from which cooper is extracted include malachite, crysocolla, and atacamite.
Aluminium is the most abundant metal, valuable for its light weight, having at. no. 13, at. wt. 26·98, and chemical symbol Al. Nearly one-twelfth of the substance of the earth’s crust is composed of aluminium compounds, but aluminium in its pure state was not readily obtained until the middle of the 19 th century, for it oxidizes rapidly, and much energy is needed to separate the metal from chemical combination. Pure aluminium is a soft white metal. It is one of the lightest of metals, its specific gravity being 2·70, and for this reason is widely used in shipbuilding and aircraft. In the pure state it is a weak metal, but when alloyed with other elements such as cooper, silicon, or magnesium, alloys of great strength are obtained. Commercially, aluminium is obtained from bauxite (q.v) and requires large supplies of electric power, as at Kitimat in Western Canada. Aluminium is much used in steel-cored aluminium overhead cables and for canning uranium slugs for reactors. Aluminium is an essential constituent in the Alcomax series of magnetic materials; and as a good conductor of electricity is used in the form of foil in electrical capacitors. In the U.S.A. the original name suggested by Sir Humphry Davy Aluminum (aloo-) is retained.
Manganese (Lat. magnes magnet). A brilliant white metal, present in small quantities in most rocks: symbol Mn, at. wt. 54·94 and at. no. 25. Discovered by Gahn in 1774 by reducing the dioxide with carbon, Manganese has a high melting point and is very reactive, and combines readily with oxygen on heating. Chiefly used in alloys, especially for manganese steel which is very tough, it also serves as a depolarizer in dry batteries, and potassium permanganate (an oxidizing agent) is used as an antiseptic and in quantitative analysis.
Silver is a lustrous silvery metal extremely malleable and ductile: symbol Ag (Lat. argentum). Known since prehistoric times, silver occurs native in Peru, but the chief ores are sulpides, from which the metal is extracted by smelting with lead. It is the best metallic conductor of both heat and electricity, and its most important compounds are the chloride and bromide which darken on exposure to light, the basis of photographic emulsions. Silver is used for tableware, Jewellery, coinage, electrical contacts and electro-plating, and as a solder it makes good metallic joints at 720ºC. The world’s greatest producer of silver is Mexico (c. 40,000,000 troy oz. p.a.) followed by the U.S.A., Canada, Peru, the Russia, Australia and Japan
