The Rainbow of Topaz

     Topaz is a gemstone that has been known about since ancient times. The mineral was named for the Mediterranean island of Topasos (which is now called the island of Zebriget.) Interestingly that island was never a source of topaz.
     Topaz crystals are orthorhombic. They are prismatic and their shape is difficult to describe. The crystal is composed of two large faces on both sides of the prism that meet like a peaked roof at the middle of the crystal. These faces give way to another face that looks like the Superman symbol at the top and bottom of the roofs on both sides of the crystal. At the top corners of these strange pentagons there are two regular pentagons that meet with two others on the other side. Atop the two Superman symbols and four pentagons there is one elongated pentagonal face that makes the apex of the crystal. The two peaked-roof shapes would meet with the two others on the opposite side to form a diamond-shaped cross-section, but they are separated by two other faces that connect to make two other peaked shapes. Like I said, topaz crystals are a little difficult to describe!
     In addition to having interestingly-shaped, prismatic crystals topaz also has a lot of interesting optical properties. Topaz is transparent and can be white, colorless, golden-yellow, green, brown, yellow, red, pink, orange, red-orange, and rarely violet and blue. Topaz often fluoresces (it glows under ultraviolet light, aka black light) and topaz’s color can be changed by heating it. Yellow topaz is often heated to change it to a more desirable pink color. Clear topaz can be turned blue by radiation. However, these synthetically-colored stones cost less than specimens that were colored naturally. Topaz can also fade in direct sunlight if exposed for prolonged periods of time, so for anyone who has a sample of the gemstone I would recommend that they store it out of the sunlight. I also wouldn't try the black-light test on it until first talking to an expert. 
     Topaz is used as a gemstone. It is the birthstone for the month of November and the traditional stone of 16^th wedding anniversaries. Topaz is also ground and used as an abrasive. It is a hard stone, harder than quartz, but it is brittle and can chip so great care must be taken when cutting it. Sometimes other gems are given names that make them sound as if they are a kind of topaz. For example citrine (a yellow-colored variety of quartz) is sometimes called “golden topaz” or “citrine topaz.” Real topaz is often called “precious topaz” to help to distinguish it from the other gems with the misleading names.
     Topaz is found in many places, but the best specimens come from places like: Finland, Sri Lanka, Myanmar, Wyoming, Utah, Maine, and Connecticut. Most of the world’s topaz comes from Brazil.
     Topaz is one of the better-known minerals that I’ve written about. Once you take into account all of its amazing optical properties it makes sense that many people have heard of it!