Topaz is a fluorine-containing aluminosilicate mineral. It is formed by the vapors emitted during the crystallization of igneous rocks. It is usually produced in rhyolite and granite pores. Topaz can be used as an abrasive material or as an instrument bearing. Transparent and beautiful topaz is a precious gem. Topaz is generally columnar or irregularly granular or block, with a variety of colors. There are generally light yellow, blue, green, red, brown, etc., with glass luster, and some colorless and transparent.
Topaz is a typical gaseous hydrothermal mineral produced in granitic pegmatite, caverns of acidic volcanic rocks, greisen, and high-temperature hydrothermal tungsten-tin quartz veins. Topaz is produced all over the world.
World-famous origins are Brazil, Russia's Ural and Pakistan's Katlan. The most important gem-quality topaz is produced in the state of Minas Gerais, Brazil. The topaz here is yellow, deep pear yellow, pink, blue and colorless. A topaz crystal was found in Brazil in 1940, weighing 240.25 kilograms, clear and flawless. The color of topazs from Russia's Ural and Pakistan's Katlan is rose-red due to Cr. Most of the world's topaz is produced in Brazilian granite pegmatite, including varieties of various colors. The largest crystal weighs 117 kg. Sri Lanka is also an important place of origin. Its topaz is mainly blue, green and colorless. Topazs from California are blue and yellow. China's topaz is produced in Inner Mongolia, Jiangxi, Xinjiang, Guangdong, and Yunnan.
- 1. Irradiation
- 2. Heating
Most blue topaz is produced by colorless topaz firstly treated by irradiation and then heated to remove yellow and brown tones. This method of color change is ideal, but it inevitably brings a nasty problem, that is, residual radioactivity. The residual radioactive half-life period of topaz is about 100 days. Therefore, the color-changed topaz cannot be immediately put on the market. Manufacturers generally store it for more than one year (more than three half-life period, at this time, the radioactivity of topaz is negligible or even negligible) before leaving the factory, so wear the color-changed topaz is safe and will not cause harm to the human body.
How long can the blue color of changed blue topaz be kept? It has always been a concern of the jewelry industry and consumers. Through fading simulation experiments and exposure to sunlight in the past 5 years, it shows that it only fades 2% to 3%, which means you can't see it fade significantly for 50 years.
Most of the world's topaz is produced in Brazil. The yellow-toned topaz produced in Central Asia, such as Brazil and Pakistan, can be heated to become pink and red.
The Meaning of Topaz
The ancients believed that the sun-like brightness of topaz can give people warmth and wisdom. Many ancient peoples use it as an amulet. It is said that wearing it can eliminate sorrow, stabilize emotions, and enhance wisdom and courage. Put a yellow topaz on the gold ornaments and hang it on the neck can avoid evil spirits and drive away demons.
The ancient Indians liked to make gold and silver rings (nine treasures) in the style of "Navaratna" to symbolize good luck. Today, topaz is used as the birthstone of November, symbolizing friendship and hope.