Precious Gems

Throughout history, precious gems have been often understood to be rubies, sapphires, emeralds and diamonds. Today, these beauties are referred to as gems like any other but the reputation of these popular gemstones makes them the most sought after pieces.

Rubies and sapphires are derived from Corundum or Aluminum Oxide, a mineral running second only to diamond as the hardest natural mineral in existence. Volcanic processes in the depths of the earth by the metamorphic processes used to transfer high heat and high-pressure into crystalline forms form this mineral. These Aluminum Oxide crystals alone are clear and only when impurities enter the rock during the recrystallization process do they form the traditional precious stones rubies and sapphires. Corundum comes in a variety of colors and depending on the translucence of the crystal-field can be highly valuable.

Sapphires are formed when small amounts of titanium and iron seep into the cooling Aluminum Oxide. These blue gemstones come in a range of shades, from pale, icy blue to a deeper cobalt color. Sapphires can also be orange-pink, purple, green, white, golden and black, depending on traces of other elements. Any sapphire other than blue is known as a ‘fancy’ sapphire. Sapphires are a trigonal gemstone meaning the natural crystal form is a three-sided prism. An interesting form of sapphire is when it is combined with the element rutile creating an asterism and gives a six pointed star shape when viewed with an overhead source of light. When a sapphire is fully saturated with impurities of chromium, which make it red, it is known as a ruby.

Rubies are the red-colored form of corundum. A ruby’s natural crystal form is a hexagonal prism. When a ruby or sapphire has impurities or weaker shades of color, they can be heat-treated to enhance their spectacular glow. Typically, heat-treated sapphires and rubies are not as valuable or as desirable as naturally deep colored and translucent stones. Rubies are very valuable and a ruby of 5 carats or more may be valued at millions of dollars.

Emeralds are derived from Beryllium Aluminum Silicate, a rare and hard mineral that is formed in intrusive, igneous origins in caves with granite and pegmatite. Some of the most valuable and famous emeralds come from Colombia. Beryl deposits hae also been found in metamorphic rocks where beryllium, aluminum and silicate elements seep out of granite and crystallize on silica-poor rock formations in the near vicinity. These beautiful green to green-blue gems are hexagonal crystals formed when the element chromium interacts with Beryl. Most precious gemstones are devalued when imputities or gas bubbles and other minerals (inclusions) or tiny fractures are formed within the gemstone. For emeralds, this is not the case. Instead, this gives the stone ‘character’ and ensures its unique, one-of-a-kind value. Other less valuable varieties of beryl gemstones include heliodor, morganite and aquamarine. The largest uncut emerald in the world, found in Carnaiba, Brazil in 1974 was 86,136 carats. The Gachala Emerald, the largest emerald crystal at 858 carats, was found in La Vega de San Juan mine in 1967.

Article Source: http://www.content.onlypunjab.com

Eric Hartwell is involved in The World's Best Home Page (please visit to read and share opinions) and Jewels To Love

Please Rate this Article

5 out of 54 out of 53 out of 52 out of 51 out of 5 

Not yet Rated