Why Is  A diamond called a gem?
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the definition of a gem is a mineral or stone that is of great value.  diamonds are very valuable, so they are indeed a gem.
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I look at it the way a diamond crystallizes under very high pressure. That is the real world example we have to learn from like the inspiring story of "It's a Wonderful Life." The diamond earns its brilliance, dazzling, purity and strength from the transformation of the endurance and becoming something that gives us "awe" and "inspiration". I think that is why an angel must earn its wings.
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Carbon. "Diamond is a transparent crystal of pure carbon consisting of tetrahedrally bonded carbon atoms."
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Lab diamonds (brand name diamonique) are chemically like diamonds from nature except that they are perfect, unlike natural diamonds which have subtle imperfections.  They are cheaper because, unlike their natural counterparts that take thousands of years and the perfect set of conditions to form,  man-made diamonds can be grown in hours/days (1 karat in 24 hours)....and it requires a lot less people, which means less paychecks.
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http://www.lifegem.com/\n\nhttp://en.wikipedia.org/wiki/LifeGem\n\nThe gems are called Lifegems, you can find information about them at the above sites or by searching for "lifegem."\nHope this is helpful :-)
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diamond will have a huge refractive index because of its structure. that can be used to detect it.
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They are artificially held up in price by DeBeers and associated firms, there are actually huge amounts of diamonds being held back from the market to maintain the price levels.  The diamond cartel also funds massive ad campaigns to create a market.  The truly valuable gems are large, uncrazed emeralds, spinels, peridots, and sapphires...especially star sapphires (red sapphires are called rubies).  Large, well cut aquamarines are good value as well.\n\nAvoid opals and pearls....opals craze very easily if not in the proper humidity, and pearls can wear through the nacre after just a few years of being worn and rubbing against clothe.
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It is believed that the Kohinoor carries with it a curse and only when in the possession of a woman will the curse not work. All the men who owned it have either lost their throne or had other misfortunes befall them. The British are wary of this curse and so far, only Queen Victoria and Queen Elizabeth have adorned the gem as sovereigns. Since Queen Victoria the diamond has always gone to the wife of the male heir to the throne.\n\n*edit* Damn! Answerer number 1 got to you first.
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The diamond is the official state gem of Arkansas. It was designated in 1967.
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It depents on the gem, of course.  Most of the ones people think of as gems, such as diamonds, sapphires &c., form as high-temperature, high-pressure phases in deep molten rock.  They don't necessarily take a long time to crystallize either.  These phases aren't stable in cooler melts, though,  so the problem is to quickly get them to the surface from their formation depths.  Some volcanic eruptions do this.  Diamonds have to come all the way from the mantle to near the surface in minutes.\n\nOther gems can form near or at the surface.  Opal, for instance, is formed by precipitation of silica from groundwater.
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Gemology (gemmology outside the United States) is the science, art and profession of identifying and evaluating gemstones. It may be considered a branch of mineralogy. Some jewelers are gemologists and are qualified to identify gems.
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A diamond is a crystal structure, and thus, exists only as a solid.  If you melt or boil a diamond (at incredibly high temperature) it is no longer a diamond, but carbon.
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Actually, diamonds are not that rare.  How come you can always find them in stores?  The reason they are so expensive is the price is set by DeBeers, a private firm that has a near monopoly in the diamond market.  DeBeers hordes thousands of diamonds and only releases a certain amount each year to keep the market adjusted to their liking. Read up on them.\n\n(Looks like tripforyou beat me to the punch)
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no a diamond is a type of rock.\n\na crystal is a type of glass.\n\nsimilar, but not quite the same.
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Diamonds are supposed to be pure 100% carbon, but due to some impurities they are classified by their shades. \nThe shades are named as: Blue white, First Cape, Second Cape, First bye, Second bye, Off color, Light yellow , Yellow \n\n\nAlso according to their shapes when they are taken from the mine, they are classified in: \n1. Close goods \n2. Spotted stones \n3. Rejection cleavage \n4. Fine cleavage \n5. Light brown cleavage \n6. Ordinary and rejection cleavage \n7. Flats \n8. Naats \n9. Rubbish \n10. Boart\n\nFinallly each colour is sub divided according to the sizes:\nFinest extra blue white, Fine Capes \nExtra blue white, Capes \nFinest blue white, Byewaters \nBlue white, Yellows \nFinest white, Finest light brown \nWhite, Light brown \nSilver Capes, Brown and dark brown \n\nAll these colors are divided into shipments of Closed Goods, Spotteds, Irregulars, Blocks, Naats, and Flats.
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Diamonds and coal have the same basic component, carbon.  Diamonds have been turned into their current form due to extreme pressure and temperature.  Diamonds come from diamond mines, not coal mines.
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A gemstone / birth stone is a collective term for all ornamental stones that possess attributes like beauty, rarity, durability.Astral gems, apart from these material properties, increase the psychic powers of an individual by their curative powers.  Astral gems also have the power to ward off the ill-effects of planets and worn in the form of birth stone..\n\n\nThe gem stone / birth stone should be set in the right metal and with the right weight.  It should be worn on the correct finger of the working hand.Each gem, with its constant source of specific rays,gives rise to constructive vibrations that have therapeutic powers. Hence wearing your appropriate birth stone will always give you luck and prosperity.