The Chronicles of Narnia

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  • Topic: Gemstone, Corundum, Aluminium
  • Pages : 3 (856 words )
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  • Published : February 10, 2013
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Kendric Ivan A. Moneva
Grade V – St. Joseph

A gemstone or gem (also called a precious or semi-precious stone, a fine gem, or jewel) is a piece of mineral, which, in cut and polished form, is used to make jewelry or other adornments. However certain rocks (such as lapis lazuli), or organic materials that are not minerals (such as amber or jet), are also used for jewelry, and are therefore often considered to be gemstones as well. Most gemstones are hard, but some soft minerals are used in jewelry because of their luster or other physical properties that have aesthetic value. Rarity is another characteristic that lends value to a gemstone.

Diamonds - A diamond (from the ancient Greek ἀδάμας – adámas, meaning "unbreakable," "proper," or "unalterable") is one of the best-known and most sought-after gemstones. Diamonds have been known to mankind and used as decorative items since ancient times; some of the earliest references can be traced to India. The hardness of diamond and its high dispersion of light – giving the diamond its characteristic "fire" – make it useful for industrial applications and desirable as jewelry. Diamonds are such a highly traded commodity that multiple organizations have been created for grading and certifying them based on the four Cs, which are carat, cut, color, and clarity. Other characteristics, such as presence or lack of fluorescence, also affect the desirability and thus the value of a diamond used for jewelry.

Sapphire - Sapphire (Greek: σάπφειρος; sappheiros, 'blue stone', which probably referred instead at the time to lapis lazuli) is a gemstone variety of the mineral corundum, an aluminum oxide (α-Al2O3). Trace amounts of other elements such as iron, titanium, chromium, copper, or magnesium can give corundum blue, yellow, pink, purple, orange, or a greenish color. Chromium impurities in corundum yield a red tint, and the resultant gemstone is called a ruby. Commonly, sapphires are worn in jewelry. Sapphires may be found...
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