Then, about two hundred years ago, people who traded in gems began to realize that these yellowish gems might be topaz, quartz, beryl, olivine, sapphire, or one of many other minerals. Many of the earliest gem traders did not realize that these yellowish stones were actually different materials. At that time yellowish gems were called "topaz" in many parts of the world. The name "topaz," and variants of the name in other languages, have been used for yellowish gemstones for at least two thousand years. We explain this process in detail on our blue topaz page. ![]() The fastest selling colors of topaz are varieties of blue that are treated by a process known as irradiation. However, some natural topaz with these colors can be heated, irradiated, coated, or treated in other ways to alter their color. ![]() Topaz that is yellow, brown, and colorless has a much lower value. Topaz with a natural blue color is very rare and valuable. Most of the world's imperial topaz is found in Brazil. Chromium is also responsible for the color in violet and purple topaz.Ī variety known as "imperial topaz" is especially valuable because people enjoy its reddish orange to orangy red colors, which often both occur in the same crystal. The most highly regarded colors are the reds and pinks, which receive their color from trace amounts of chromium. Topaz occurs in a wide range of natural colors however, most natural topaz is colorless. But, as the topaz crystal expanded, it pushed the tiny crystal in the direction of growth, and a wispy stream of inclusions within the topaz was the result. The tiny crystal made it difficult for the topaz below it to grow properly - it had become an obstacle to growth. Instead it is a tiny crystal of an unidentified mineral that started to grow on the surface of a much larger topaz crystal. These colors are very rare.Ĭomet Tail Inclusion in Topaz: It looks like a comet flying through a gemstone. The most valuable colors for use in jewelry are natural pink, orange, red, purple and blue. Diamond, corundum, and chrysoberyl are the only commonly known minerals that are harder than topaz. Every student who takes a physical geology course learns about the exceptional hardness of topaz. It has a hardness of 8 on the Mohs hardness scale, making it the hardest silicate mineral. One of the best-known physical properties of topaz is its hardness. Hardness, prismatic crystals, sometimes striated, cleavage, specific gravity. Occurs in a wide range of treated colors, most often blue.Ĭolorless - harder than the streak plate. Natural colors include: colorless, yellow, orange, brown, red, pink, blue, green. Today, over 200 years later, his hardness scale is still used by students and geologists throughout the world to identify mineral specimens. In 1812, Friedrich Mohs developed a set of 10 standard minerals that could be used to assign a relative hardness to minerals and other materials. The most affordable and frequently purchased are blue topaz and mystic topaz that have received their colors from treatment. Natural topaz colors include rare and valuable yellow, orange, pink, red, purple, and blue. Topaz obtains much of its popularity from its beautiful colors and its status as a birthstone. It is best known for being these four things: Topaz is a rare silicate mineral with a chemical composition of Al 2SiO 4(F,OH) 2. Specimens and photos by Lockwood and Sloan. The rarity and value of these natural topaz colors is lowest at the bottom of the photo and highest at the top. At the top are orangy pink and purplish pink gems that are sometimes called "pink topaz". Some gemologists would call these two specimens "imperial topaz" because they display reddish orange pleochroic colors on both ends of the gem. Starting at the bottom is yellow topaz, sometimes called "golden topaz". Natural Topaz Colors: A collection of faceted topaz in a variety of colors.
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