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AQUAMARINE March 7, 2014

Filed under: Gemstones — vapspecialthings @ 8:30 am
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Aquamarine

Aquamarine, the modern March birthstone as adopted by the American National Association of Jewelers in 1912, is a variety of Beryl that is transparent and of various shades of blue and blue-green; almost all the specimens of the preferable sky-blue in color are (since 1920) the result of heat treatment applied to greenish or yellow-brown beryls. The stones are dichroic, and are usually cut as a brilliant or step cut. They resemble the Emerald (the chemical composition is identical, as is the hexagonal crystal form) but the stones are paler and, being less rare, are much less valuable. They also resemble euclase and blue Topaz, from all of which (as well as from glass imitations and synthetic gemstones) they can readily be distinguished. Aquamarines on the market today are usually faceted, but when cut as a cabochon, they may display a cat’s eye effect known as asterism. 

Aquamarine Cat Eye

There are many sources, but Brazil has produced the finest and some very large specimens, e.g. one found in 1919 weighing 243 Lb. Some ancient aquamarines were engraved with portraits, e.g. one with a portrait of Julia, daughter of the Roman Emperor Titus. The synthetic stone resembling aquamarine is the blue Synthetic Spinel.

Folklore, Legend, and Healing Properties:

Since early times, aquamarine has been believed to endow the wearer with foresight, courage, and happiness. It is said to increase intelligence and make one youthful. As a healing stone, it is said to be effective as a treatment for anxiety and in the Middle Ages it was thought that aquamarine would reduce the effect of poisons.

A legend says that sailors wore aquamarine gemstones to keep them safe and prevent seasickness. 

Aquamarine 3

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AMETHYST February 17, 2014

Filed under: Gemstones — vapspecialthings @ 12:49 am
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Amethyst

Traditionally February’s birthstone, Amethyst is a variety of Quartz that is transparent and crystalline, usually deep purple to pale bluish-violet; the hues are sometimes mingled in the same stone, owing to irregular color zoning, and some show patches of yellow. Other colors are reddish-mauve (Siberian stones), reddish-violet (Uruguayan stones) or grey-mauve (Mexican stones).

Specimens containing inclusions of goethite or other fibrous minerals are polished as cats eye’s. Amethysts have been set in globular or pear-shaped pendants and as pierced beads for necklaces and ear-drops. Some large stones have been embellished by having set into them a design of small diamonds.

Amethyst was used as a gemstone by the ancient Egyptians and was largely employed in antiquity for intaglio engraved gems.

For centuries, people have believed this mystical stone possesses healing power: The Greeks believed amethyst gems could prevent intoxication, while medieval European soldiers wore amethyst amulets as protection in battle in the belief that amethysts heal people and keep them cool-headed. Beads of amethyst were found in Anglo-Saxon graves in England.

In the 19th century, the color of amethyst was attributed to the presence of manganese. However, since it is capable of being greatly altered and even discharged by heat, the color was believed by some authorities to be from an organic source. Ferric thiocyanate has been suggested, and sulfur was said to have been detected in the mineral.

When natural amethysts (not the variety from Madagascar) are heated, the color changes to pale yellow (sometimes then mistaken for Citrine, but distinguishable by its dichroism); when the heat is increased, it changes to dark yellow or reddish-brown and, when increased further, to milky white. Some Brazilian amethysts when heated change color to green.

amethyst 3

 

 
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