Topaz
Topaz is the traditional birthstone for the month of November (imperial), and blue topaz is the traditional birthstone for the month of December.
Topaz is an aluminum silicate fluoride hydroxide (Formula: Al2(SiO4)(F,OH)2). Its well-formed crystals have a characteristic lozenge-shaped cross-section, and striations parallel to their length. They are found in a wide range of colors, with the sherry-yellow tones from Brazil being particularly valuable, but natural pink stones are rare. In 1750 a Parisian jeweler discovered that yellow Brazilian topaz becomes pink on exposure to moderate heat, and most pink topaz today is heat-treated yellow material. Some blue topaz is almost indistinguishable from aquamarine with the naked eye. However, much of the deep blue topaz on the market is derived from irradiated and heat-treated colorless topaz. The natural color in many cases is unstable: for example, brown topaz from Siberia and Utah is prone to bleaching by sunlight.
Colorless topaz is sufficiently refractive that when brilliant-cut, it has been mistaken for a diamond. The Braganza diamond (1,640 carats) in the Portuguese crown during the 17th century was thought then to be the largest diamond ever found but is now thought to have been a colorless topaz.
Topaz is formed by fluorine-bearing vapors given off during the last stages of crystallization of various igneous rocks, typically occurring in cavities in rhyolites, granites, pegmatite dikes, and hydrothermal veins. It is also found in alluvial depositis as water-worn pebbles. Perfect cleavage causes crystals to break easily, with the result that part of a crystal often remains in the matrix.
Gem topaz is found in Colorado, Texas, and California; the Caringorm Mountains of Scotland; Sri Lanka; Mayanmar; Australia; Tasmania; Pakistan; and Mexico. However, aside from Brazil, Russia and Nigeria are the major producers of Topaz. The Brazilian state of Minas Gerais is the world's largest producer of topaz, and the world's largest preserved crystal, weighing 596 lb (271 kg), is from there. Beautiful crystals come from Japan, and the first modern use of the term "topaz" occurred in 1737 when applied to the abundant yellow crystals from Saxony, Germany. The legendary island of Topazios, just off the coast of Egypt in the Red Sea, and now called Zebirget, is thought to be one source of the name "topaz". It is also thought to derive from tapaz, the Sanskrit word for "fire". Many authorities believe that the stone called topaz today was unknown to the ancients and that the name topazos referred to olivine (peridot), as Topazios was a well-known locality for that gem. It follows that the "topaz" in the Old Testimant may also have been peridot. The gem was used in ancient Egypt, Greece, and Rome, the Roman source being faraway Sri Lanka.
Imperial topaz is also known as "precious topaz". It is the most sought after natural topaz. Considered to be the color of the setting sun, imperial topaz gets its name from the Russian tsars of the 17th century. This is because the tsars claimed exclusive rights to the pink topaz gemstones that were mined in Russia. Imperial topaz is less common than other types of naturally occurring topaz, which makes it more valuable. Imperial topaz was traditionally considered to be orange with red dichroism, (this means that when tilted in the light, imperial topaz can appear red or orange), but nowadays it is more widely defined as yellow, pink, red, lavender-pink, and peach-pink topaz.
The ancient Greeks believed that topaz gave them strength. In Europe during the Renaissance (the period from the 1300s to the 1600s) people thought that topaz could break magic spells and dispel anger. For centuries, many people in India have believed that topaz worn above the heart assures long life, beauty, and intelligence. The name for imperial topaz originated in nineteenth-century Russia. At the time, the Ural Mountains were topaz’s leading source, and the pink gemstone mined there was named to honor the Russian czar. Ownership of the gem was restricted to the royal family.
If worn on the left arm, some believed a topaz amulet could protect the wearer from dark magic. In addition, this could relieve arthritis pain, improve digestion, aid in weight loss, and attract love. If taken in a potion, some believed it could cure an even wider range of ailments. St. Hildegard recommended the topaz as a cure for dim vision. After soaking a topaz in wine for three days and nights, rubbing the stone gently on the eyes would help. Perhaps this connection to vision helps explain another popular belief, that topaz could render its wearer invisible. If kept in the home, some believed topaz could ward off accidents and fires. If kept under a pillow, it could prevent nightmares.
