Link Directory Donations Mobile Site. Chemical Formula. Aluminum fluoro-hydroxyl-silicate. Colorless, white, yellow, orange, brown, pink, light purple, gray, light blue, greenish blue, green. Occasionally multicolored. Crystal System. Crystal Forms and Aggregates. Prismatic , tabular , and stubby crystals, usually striated and sometimes quite large.
Crystals may contain numerous face s, and often have complex termination s. Also occurs columnar , massive , grainy , radiating , and as rounded, waterworn pebbles. Topaz may also be in the form of feldspar as a pseudomorph. Transparent to opaque.
Specific Gravity. In Group. Silicates ; Nesosilicates. Striking Features. Great hardness and perfect basal cleavage. In igneous environments in granite pegmatite s and in rhyolite. Occasionally in sedimentary alluvial deposit s. Rock Type. Popularity Prevalence Demand These colors are often heated, irradiated, coated, and treated in other ways to alter their color. Topaz Treatment Methods: Colorless topaz, also known as white topaz, top left can be irradiated and heated to produce gems with a blue color top right.
Irradiation alone can produce a pale pink color bottom right. Coating with certain metallic oxides can produce a vivid pink color bottom left. Most topaz in commercial jewelry today is colorless material that has been heated, irradiated, or coated to improve its color.
The name "topaz" and many language variants have been used for yellowish gemstones for at least two thousand years. At that time yellowish gems were called "topaz" in many parts of the world. Many of the earliest gem traders did not realize that these yellowish stones were actually different materials.
Then, about two hundred years ago, people who traded in gems began to realize that these yellowish gems might be topaz, quartz , beryl , olivine , sapphire , or one of many other minerals.
They also learned that topaz occurred in a wide range of colors other than yellow. If you visited a jewelry store as recently as fifty years ago and asked to see topaz, you would likely have been shown gems that were in the color range of yellow, orange, and brown.
Starting in the s and s, the most common color that you would be shown began to be blue. This blue color was usually produced by treatments that converted colorless topaz into a more marketable gemstone. These treatments are sold under the trade name of "mystic topaz.
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 topaz 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. 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. Blue Topaz: Faceted ovals of two colors of blue topaz that are popular today. On the left is a "Swiss Blue" topaz weighing 2. On the right is a "London Blue" weighing 2. Both stones were colorless topaz mined in Brazil.
After faceting they were irradiated and heated to produce the blue colors. Blue topaz with a color produced by treatment is the most common color of topaz in commercial jewelry today. The type of irradiation used to transform colorless topaz into blue topaz can cause the irradiated material to become slightly radioactive. Fortunately, the radioactivity level of the topaz begins to decline as soon as treatment is complete. It eventually declines to a level that is safe for the topaz to be handled during manufacturing and be sold to the public in jewelry.
In the United States, the Nuclear Regulatory Commission requires all irradiated gems and gem materials to be securely stored until their radioactivity decays to a level that is safe for manufacturing and sale.
This is done to protect employees of the gem and jewelry industry and the jewelry-buying public. All companies who distribute newly irradiated gems in the United States must be licensed by the Nuclear Regulatory Commission. They must also conduct radiological surveys of all materials in secure storage to be sure that no gems are released until their radioactivity declines to a level that will not pose any health risks.
The Nuclear Regulatory Commission has detailed information about irradiated topaz and other gemstones on their website. They also have answers to frequently asked questions.
Two answers that we believe will be of interest to our readers are quoted in the box on this page. You can read the rest by visiting the NRC website. These valley fills were once thought to be deposited by water, but now many of them are believed to have been deposited by ground surges of hot ash. The Topaz Mountain Rhyolite has many vuggy areas, which often contain champagne-colored topaz crystals.
USGS image. Placer Topaz: Topaz has a high specific gravity, and because of that it is commonly concentrated by stream currents into placer deposits. Much topaz has been produced from placer deposits in Brazil and Nigeria. The topaz pebbles in the photo above are from Brazil and were rounded and frosted during stream transport. The fluorine in its composition is a limiting factor on its formation. Fluorine gas in concentrations high enough to form minerals only occurs in a few geologic environments.
Most topaz grows as crystals within the veins and voids of igneous rocks. This topaz is found in the cavities of a pegmatite , or in the vesicles and intergranular spaces of rhyolite. These topaz crystals grow during the late stages of magma cooling and while degassing releases the fluorine necessary for topaz crystal growth.
Precipitating in cavities, topaz sometimes develops nicely formed crystals. These crystals can have excellent clarity and can be used as a gem material. Topaz Symbolism The ancient Greeks believed that topaz could make a wearer invisible. The gem was also thought to calm anger and balance strong emotions. A symbol of honor and strength, topaz was believed to bring longevity and wisdom.
It is said to soothe, heal, re-motivate, and bring the wearer strength, loyalty, beauty, protection, healing, weight loss, joy, generosity, abundance, wisdom, enlightenment, knowledge, good health, virtues of leadership, and love. Begin typing your search term above and press enter to search. Press ESC to cancel. Skip to content Home Articles Where is Topaz most commonly found? Ben Davis March 8, Where is Topaz most commonly found?
How much does topaz cost? How can you tell if Topaz is real? Is Mystic Topaz expensive? What are the benefits of wearing topaz? Who should not wear topaz? Is Topaz Lucky? In which finger should Topaz be worn?
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