Topaz is a rare silicate mineral and obtains much of its popularity from its beautiful colors and its status as a birthstone. Topaz occurs in a wide range of natural colors; however, most natural topaz is colorless. The most highly regarded colors are the reds and pinks, which receive their color from trace amounts of chromium. The name "topaz," and variants of the name in other languages, have been used for yellowish gemstones for at least two thousand years. At that time yellowish gems were called "topaz" in many parts of the world. Many of the earliest gem traders did not realize that these yellowish stones were actually different materials. Most topaz grows as crystals within the veins and voids of igneous rocks. This topaz is found in the cavities of a pegmatite, or in the vesicles and intergranular spaces of rhyolite. Topaz is found in many locations worldwide where rocks like pegmatite and rhyolite are formed.