Turquoise
 
December Birthstone.  11th Anniversary Gemstone.   Among the oldest known gemstones, Tourquoise has been mined since approximately 3200 B.C.    Turquoise graced the necks of Egyptian Pharaohs and adorned the ceremonial dress of early Native Americans.   In the ancient Persian kingdom, the sky-blue gemstones were worn round the neck or wrist as protection against unnatural death.   If they changed color, the wearer was thought to have reason to fear the approach of doom.    Meanwhile, it has been discovered that the turquoise certainly can change color, but that this is not necessarily a sign of impending danger.    The change can be caused by the light, or by a chemical reaction brought about by cosmetics, dust or the acidity of the skin.
 
Turquoises were often worn on the turban, often surrounded with pearls, in order to protect their wearer against the 'evil eye'.    As talismans, they adorned daggers, sabres and the bridles of horses.    It was not until the time of the crusades that they came to Europe.    During that period the name 'Turquoise' originated, meaning 'Turkish'.
 
With the finest color being an intense blue, Turquoise occurs as an opaque, light to dark blue or blue-green gem.  Turquoise is a copper aluminium phosphate with a hardness of 6 on the Mohs Scale.  A whole range of hues from sky blue to grey-green Turquoise, the most popular being a robin-egg-blue, is mostly found in places with a high concentration of copper in the soil.  The blue color is created by copper, the green by bivalent iron and a certain amount of chrome.   Narrow veins of other materials, either isolated or running as a network through the stone, may be seen.   The veins are usually black, brown, or yellowish-brown in color.   Known as the matrix, these veins of color are sometimes in the form of an intricate pattern, called a 'spider web'.   These lively, more or less regular patterns are known as 'Turquoise matrix'.   The crystals are microscopically small and can hardly ever be recognised with the naked eye.   Turquoise occurs as a fillung in veins or crevices, or in the form of nuggets.   The most well-known deposits are in the USA, Mexico, Israel, Iran, Afghanistan and China.   The most beautiful Turquoises, in a splendid light blue, come from deposits in North Iran.
 
Rarely faceted, Turquoise is cut into cabochons or beads, or into some more imaginative shape.
 
Since the color may pale when the stone has been worn for a long time, even high-quality stones today are treated with wax or plastic and subsequently hardened.   This treatment makes the sensitive gemstone more resistant.  Sometimes the Turquoise is sealed with a synthetic resin resulting in a fresh color and good durability.   Many are dipped in a coloring medium before being subjected to durability.   Turquoise may also be permeated with colorless oil or wax, which is considered not as stable as plastic.   Some Turquoise is dyed to improve its color, but rarely, as this is an unstable enhancement.   There is also such a thing as a 'reconstructed Turquoise', which is made from pulverised Turquoise.
 
Because of its sensitivity, Turquoise is almost always subjected to treatment of one kind or another, though this may take any number of different forms.    For this reason, Turquoise which has a good natural color and is simply hardened with colorless wax or synthetic resin has a much higher value than stones whose color has been 'improved' (altered).
 
 
 
 
 
 
 
GB Jewelers, Inc.
Under the Clock Tower
675 SE Marlin Avenue, Suite 1  /  PO Box 999
Warrenton, OR 97146
800-869-1481

Latitude:  46.159033 / Longitude: -123.9055280
 
 
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