November's popular birthstone, topaz, is widely admired for its vibrant array of colors, including yellows, oranges, blues, greens, reds, browns, pinks and purples.
The topaz in the photo, above, are part of the Smithsonian's National Gem Collection and can be seen up close and personal in the Janet Annenberg Hooker Hall of Geology, Gems, and Minerals at the National Museum of Natural History in Washington, DC. Originating from Russia, Japan, Madagascar, Ukraine, Brazil and the US (Texas), the topaz in this grouping range in weight from 18 to 816 carats.
Topaz — especially the yellow-to-orange varieties — has been misunderstood and misidentified for more than 2,000 years. Topaz gets its name from Topazios, the ancient Greek name for a tiny island in the Red Sea. The island is now known as Zabargad Island, the largest of a group of islands in Foul Bay, Egypt. It is very likely that the “topaz” mined there in ancient times was actually a yellow-green variety of peridot.
Before 1950, many “gem experts” shared the misconception that all yellow gems were topaz and that all topaz was yellow. In fact, citrine (November’s alternate birthstone) and even smoky quartz are still mistaken for topaz even though quartz and topaz are unrelated minerals
Today, we know that topaz is allochromatic, which means that its color is caused by impurities in the gem's chemical makeup or defects in its crystal structure, according to the Gemological Institute of America. For example, the presence of the element chromium results in natural pink, red and violet-to-purple colors, while imperfections at the atomic level can cause yellow, brown and blue colors. Pure topaz will be colorless.
Brazil is the largest producer of quality topaz, but the gem variety is also mined in Pakistan, India, Sri Lanka, Russia, Australia, Nigeria, Germany, Mexico and the US (specifically California, Utah and New Hampshire). Topaz rates an 8 on the Mohs hardness scale, making it a durable and wearable gem.
Topaz is a talisman for the sign of Sagittarius and is the suggested gift for the 23rd or 50th wedding anniversary.
Credit: Photo by Chip Clark/Smithsonian and digitally enhanced by SquareMoose.