November 11, 2019

If your birthday is in November, your birthstone—the gem associated with the month of your birth—is the topaz. Topaz is a compound of aluminum, fluorine, silicon, oxygen, and hydrogen. The mineral is commonly white or light colored, but trace impurities can give topaz crystals a wide variety of colors. Topaz is often cut into gems, and its myriad colors give it a lovely versatility in jewelry.

Topaz is the birthstone for the month of November. Credit: © Albert Russ, Shutterstock

The ancient Greeks believed topaz increased physical strength. In the Middle Ages, topaz was worn to ward off danger, break magic spells, or maintain good health. Topaz was also thought to improve eyesight and at times make a person invisible. People thought that beneath a pillow, topaz prevented nightmares, and in a home the gem protected from fires. Gold-colored topaz was thought to attract wealth as well as the favors of royalty or high government. In India, topaz was believed to encourage long life, beauty, and intelligence. “Imperial” topaz was a favorite gem of the Russian  czars.

Small amounts of topaz occur in both igneous rocks (rocks formed when molten rock cools and solidifies) and metamorphic rocks (rocks formed by heat and pressure). Jewelers cut transparent topaz crystals into gems. The most desirable topaz gems range in color from completely colorless to gold, orange, blue, and pink. Exposing some topaz crystals to heat or radiation can dramatically enhance or even change their color.

Jewelers sell blue topaz as a substitute for the gem aquamarine (a birthstone of March). Citrine, a yellow or brownish variety of quartz, is sometimes sold as a substitute for topaz. Topaz is found in many parts of the world. Brazil produces most of the world’s gem-quality topaz. Many museum collections have large, beautiful topaz crystals that weigh hundreds of pounds or kilograms. The gem gallery at the National Museum of Natural History at the Smithsonian Institution in Washington, D.C., is home to the 48.86-carat Whitney Flame Topaz. It is one of the finest imperial topaz gemstones in the world, notable for its large size and fiery red color.

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Birthstones, according to tradition, bring good luck when worn by a person born in the associated month. Credit: WORLD BOOK illustrations by Paul D. Turnbaugh

According to tradition, a birthstone brings good luck to a person born in its month. Each birthstone also corresponds to a sign of the zodiac. The belief in birthstones may have come from a Bible story about Aaron, the first high priest of the Israelites. The story describes Aaron’s breastplate, which was decorated with 12 precious stones. Early writers linked these stones with the 12 months of the year and the 12 signs of the zodiac. The custom of wearing a stone that represented a person’s zodiac sign probably originated in Germany or Poland in the 1700′s.

Jan. 9, 2012

The mystery of how a highly unusual material found in a rock from a Russian mountain could have been created naturally on Earth may have been answered: It didn’t. A new study by scientists from Princeton University suggests that the material, called a quasicrystal, came from outer space in a meteorite. Moreover, the meteorite may be older than Earth itself. The finding indicates that materials that could never form naturally on Earth can form in space–which has scientists wondering what other materials are out there.

In a crystal, atoms are arranged in an orderly manner, with a regularly repeating pattern. The atoms in a quasicrystal also have an orderly arrangement, but they do not have a regularly repeating pattern. Scientists once thought that quasicrystals were an impossibility. In fact, when Daniel Shechtman, an Israeli engineer, reported his discovery of quasicrystals in 1982, the scientific community dismissed his findings completely. (In 2011, Shechtman won the Nobel Prize in chemistry for his discovery.) Several years after his discovery, other scientists made more quasicrystals in various arrangements. Then in 2009, scientists reported finding a naturally occurring quasicrystal in a rock from Russia’s Koryak Mountains.

Now Princeton scientists have reported that the Koryak quasicrystal appears not to have formed naturally on Earth after all. The rock apparently is the remains of a meteorite that formed 4.5 billion years ago, even before Earth had taken shape in the early solar system. In the rock sample, the scientists found a tiny grain of a mineral called stishovite, which occurs only at the kind of high pressure achieved in meteorite impacts and collisions. The quasicrystal was encased in the stishovite.

Both quasicrystals and crystals, such as these salt crystals, contain atoms that are arranged in an orderly pattern. But the atoms in quasicrystals do not follow the kind of repeating pattern found in crystals. (c) Charles Falco, Science Source from Photo Researchers

Many quasicrystals have practical uses. Certain quasicrystals can be particularly strong and hard. They are mixed with such metals as aluminum and steel and other alloys (mixture of metals) to increase a metal’s strength and hardness. Quasicrystals may also exhibit nonstick abilities, such as those found in the nonstick coatings on cookware.

Additional World Book articles:

• Mineral
• Symmetry