Texas Blue Topaz - the Texas State Gemstone
Topaz is the Texas state gemstone as well as the birthstone for the month of November. It occurs naturally in many colors including blue, orange, brown, green, pink, beige and red. Colorless topaz, a the most common variation, can be treated by irradiation to produce a wide range of shades of blue. Thus treated, blue topaz is one of the most popular and widely used of all gemstones.
Blue topaz was adopted as the state gemstone as the result of legislation approved March 26, 1969. The same legislation also named petrified palm wood as the state stone. It occurs naturally in many colors including blue, orange, brown, green, pink, beige and red. It is especially common in the East Texas Piney Woods region and along the Gulf Coast.
Topaz has fascinated human cultures for hundreds of years. It occurs in many colors, not just blue, and is used in jewelry because of its hardness and beauty. The intense blue color of this topaz specimen is natural. Many times it also has inclusions, or imperfections, inside the gem. Look closely at this specimen, and you'll see clear through to the other side. It is very rare to find a large topaz like this one so clear, and with natural blue color! Blue topaz is found in Mason County, though not all topaz locations have blue.
This hard gem is an aluminum fluorisilicate Al2[F/OH2/SiO4] and is next in hardness to carborundum and diamonds (two of the hardest natural minerals around). Until the 1950s, topaz was generally known as a yellow or golden gemstone. Since then, routine radiation and heat treatment of pale-colored topaz to turn it blue has changed the modern public's perception of this gem. Constructed of atoms of aluminum, silicon, fluorine, and oxygen, topaz usually is colorless to pale blue or yellow -- although pink stones can be produced by heating the golden brown topaz from Ouro Preto, Brazil.
Thomas Range topaz obtained their color from natural radiation during their formation in vent pipes which trapped volatile gases in cavities within the host rhyolites. When unearthed they glow with a vibrant sherry color and with exposure to direct sunlight for awhile will generally turn clear. The sunlight (also UV radiation) reacts with the color centers in the topaz crystal structure displacing electrons which in turn change the color. However, some locations do produce topaz that fade to a beautiful pink color. Some topaz are "tougher" than others and do not have as weak a cleavage plane as the Thomas Range topaz which usually they cleave with a flat top. A favorite location for the mineral collectors and rock hounds is called "The Cove" on the southern end of the Thomas Range.
Wear topaz only if you wish to be clear-sighted: legend has it that it dispels all enchantment and helps to improve eyesight as well! The ancient Greeks believed that it had the power to increase strength and make its wearer invisible in times of emergency. Topaz was also said to change color in the presence of poisoned food or drink. Its mystical curative powers waxed and waned with the phases of the moon: it was said to cure insomnia, asthma, and hemorrhages. Topaz is the birthstone of November.