This is a shade of blue, greenish kind of blue which has a physical effect on me. I get really nauseous when looking at this colour.
I rememer a taking some sort of exam about Mozart in music class when I was thirteen. I was wearing a knitted sweater, a gift from my grandmother. An ugly turquoise sweater. I suddenly got very aware of the colour, staring at the sleeve as I was writing down the answers. Instantly I started feeling sick and had to leave the classroom, go home and change the sweater.

Years later my mother told me about a nightgown she once had. A turquoise nightgown. But she could not wear it when my father was in the same room. The first time he saw it, he just stared at it saying "Can´t you change into something else, that colour makes me nauseous."

Spooky!

Opaque gemstone of a light blue or blue-green color. The blue color comes from copper, the green from iron. It's usually found in a matrix of brown or gray rock, so that it is hard to find a gem-size chunk of turquoise without any streaks of other rock (often veins of black manganese) running through it -- the more matrix a piece contains, the lower the price of that piece of turquoise. Robin's-egg blue is the most sought-after color.

Turquoise is rather porous, so it is often oiled or waxed after polishing to keep it from absorbing things from its environment (sometimes also to get it to absorb a dye). Too much heat will change the color of the stone, usually washing out the color; heat will also make an oiled/waxed gem "sweat" a little.

Sometimes "reconstructed" turquoise is seen on the market; this is small bits of natural turquoise glued together. Synthetic turquoise has also been available for about 25 years. On extremely rare occasions, clear turquoise crystals are found in nature -- these are very expensive.

Chemical Composition: CuAl6((OH)2/PO4)4.4H2O
Mohs' Hardness: 5-6
Specific Gravity: 2.90-2.80
Cleavage: None
Transparency: Opaque
Refractive Index: 1.61-1.65
Double Refraction: +.0.04
Dispersion: None

The mineralogical name for turquoise is calaite, which is derived from a name used by Pliny to describe the stone. However, this name is rarely used, it is more commonly called Oriental Turquoise, true or mineral Turquoise or Turquoise de la vieille roche, or just plain turquoise. The name, turquoise, means Turkish stone, as this stone came to Europe through various trade routes, origionating in Persia, the Sinai Peninsula or further east, all of which went through Turkey.

Turquoise is always opaque and varies in color from a light sea green to a deep blue. The color comes from Copper and Iron sulfate found throughout the stone. The coloration comes from various colored bands spread evenly across defined spaces in the stone. When a heat of 482°F (250°c) is applied to the stone discoloration occurs, as blues change to a dull green color. Very thin sections of the gem are colorless to a light yellow in hue. Turquoises are also known to lose their color in sunlight. A dying technique has been formed to counteract this bleaching effect. But the technique does not work perfectly, and the dye on the stone can be chipped off with a knife.

Turquoise is found in cracks and cevices of other rocks. It is found in irregularly shaped masses. While turquoise was thought to be amorphous for a long time, it actually consists of an array of very small microcrystals. Geographically, turquoise is found all over the globe, from Mexico and New Mexico to Iran and Afghanistan, Tibet, Israel, eastern Austrailia and Virginia. One of the first clutches of turquoise was found on the Sinai Peninsula, but this was mined out over 4,000 years ago.

Today, the more blue a turquoise is, the more expensive it is considered. However, Mexicans and southwestern Native Americans did not share this belief. They considered both the blue and the green variations equally valuable. In fact, they called all blue/green stones that were similar to turquoise, chalchihuitl. This included jadeite, turquoise and amazonite.

In ancient Tibet, turquoise, along with gold, was the most common offering to gods and demons. Thrones for kings and Lamas were often adorned with turquoise, as was a special cape the Lamas wore. In early 17th century Europe, turquoise was thought to change its opacity as the health of the wearer changed. One author at the time claimed "A true wife should be like a turquoise stone, clear in heart in her husband's health, and cloudy in his sickness."


Sources:
Precious Stones, by Dr. Max Bauer. Charles E. Tuttle Company: Rutland Vermont and Tokyo, Japan, 1969
Gemstones of the World, by Walter Schumann. Sterling Publishing Co., New York, 1979
Simon and Schuster's guide to Rocks and Minerals, Simon and Schuster Inc. New York, 1978
The Magic of Jewels and Charms, Dr. George Frederick Kunz. J.B. Lippincott company, Philadelphia and London, 1915

Tur*quoise", Tur*quois" [F. turquoise; cf. Pr. & Sp. turquesa, It. turchese, turchina, LL. turchesius, turchina; -- so called because first brought from Turkey. See 1st Turkey.] Min.

A hydrous phosphate of alumina containing a little copper; calaite. It has a blue, or bluish green, color, and usually occurs in reniform masses with a botryoidal surface.

[Formerly written also turcois, and turkois.]

Turquoise is susceptible of a high polish, and when of a bright blue color is much esteemed as a gem. The finest specimens come from Persia. It is also found in New Mexico and Arizona, and is regarded as identical with the chalchihuitl of the Mexicans.

 

© Webster 1913.


Tur*quoise", a.

Having a fine light blue color, like that of choice mineral turquoise.

 

© Webster 1913.

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