What is Topaz? Topaz is a silicate mineral of aluminium and fluorine. It is used as a gemstone in jewelry and other adornments. Common topaz in its natural state is colorless. Though trace element impurities can make it pale blue or golden brown to yellow orange. This stone is a nesosilicate mineral. It is one of the hardest naturally occurring minerals, and has a relatively low index of refraction. It occurs in many places in the world.
Topaz in its natural state is a golden brown to yellow. The characteristic which means it is sometimes confused with citrine, a less valuable gemstone. The specific gravity of all shades of this stone, means that it is considerably heavier than citrine. This difference in weight can be used to distinguish two stones of equal volume.
Likewise, glass stones are also much lighter than equally sized topaz.
A variety of impurities and treatments may make topaz wine red, pale gray, reddish-orange. Pale green, or pink (rare), and opaque to transparent. The pink and red varieties come from chromium replacing aluminium in its crystalline structure.
Imperial topaz is yellow, pink, rare, if natural. Or pink-orange. Brazilian imperial topaz can often have a bright yellow to deep golden brown hue. And sometimes even violet. Many brown or pale topazes are treated to make them bright yellow, gold, pink, or violet colored. Some imperial topaz stones can fade on exposure to sunlight for an extended period of time. Naturally occurring blue topaz is quite rare. Typically, colorless, gray, or pale yellow and blue material is heat treated, And irradiated to produce a more desired darker blue.
Mystic topaz is colorless topaz which has been artificially coated via a vapor deposition process giving it a rainbow effect on its surface.
Although very hard, topaz must be treated with greater care than some other minerals of similar hardness. Because of a weakness of atomic bonding of the stone’s molecules along one or another axial plane . This gives this stones a tendency to break along such a cleavage plane if struck with sufficient force.
Diamonds, for example, are composed of carbon atoms bonded to each other with equal strength along all of its planes.
Topaz is commonly associated with silicic igneous rocks of the granite and rhyolite type. It typically crystallizes in granitic pegmatites or in vapor cavities in rhyolite lava flows. Including those at Topaz Mountain in western Utah and Chivinar in South America. It can be found with fluorite and cassiterite in various areas including the Ural and Ilmensky Mountains of Russia. In Afghanistan, Sri Lanka, Czech Republic. Also in Germany, Norway, Pakistan, Italy. Sweden, Japan, Brazil, Mexico. And Flinders Island, Australia; Nigeria and the United States.
Some clear topaz crystals from Brazilian pegmatites can reach boulder size and weigh hundreds of pounds.
The Topaz of Aurangzeb, observed by Jean Baptiste Tavernier weighed 157.75 carats. Large, vivid blue topaz specimens from the St. Anns mine in Zimbabwe were found in the late 1980s. Colorless and light-blue varieties of topaz are found in Precambrian granite in Mason County, Texas within the Llano Uplift. There is no commercial mining of topaz in that area.
It is possible to synthesize topaz.
Topaz obtains much of its popularity from its beautiful colors and its status as a birthstone. Natural topaz colors include rare and valuable yellow, orange, pink, red, purple, and blue. The most affordable and frequently purchased is blue topaz that has received its color from treatment.
Topaz is the original modern birthstone for the month of November. Its position as a birthstone contributes to the gem’s popularity. Topaz jewelry can be found for sale in almost every jewelry store.
In 1952, Jewelers of America made a few modifications to the list of modern birthstones. That was when citrine, a yellow to orange to reddish brown variety of quartz, was added as a second birthstone for the month of November.
Today most topaz offered in department stores and mall jewelry stores at low to moderate prices has been treated in a laboratory. Colorless topaz can be heated, irradiated, and coated with thin layers of metallic oxides to alter its color.
Natural blue stone is extremely rare and is usually pale blue. Almost all of the blue topaz offered in stores today is colorless topaz that has been irradiated. And then heated to produce a blue color. “Swiss blue” and “London blue”. It are trade names for two of the most common varieties of treated blue topaz seen in today’s market.
Natural pink to purple topaz is also extremely rare. But these colors can be produced in a laboratory as well. The starting point is a stone cut from colorless topaz. It is first heated and then coated with a layer of metallic oxide to produce the pink color. If coated stones are worn in jewelry. Over time the coating can wear thin. Or wear through at points on the stone where abrasion occurs.
Some topaz is coated with a metallic oxide that gives the stone a multicolored iridescent luster. These stones, known as “mystic topaz,” appear to change color if the observer moves the stone under a light or changes the angle of observation. These coatings are also thin and can be worn through during normal wear.
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