Topaz contains the element fluorine, which only occurs in high concentration in a few geologic environments. Topaz usually forms along fractures and in cavities of igneous rocks like rhyolite, granite or pegmatite. The crystals grow in the late stages of a magma cooling, when there is enough fluorine to enable the formation of topaz. Some topaz crystals grow after hot fluids (hydrothermal solutions), rich in fluorine, flow through cracks in rocks that have already cooled. Topaz can also form in metamorphic zones. Topaz is one of the last minerals to form in an igneous rock as it cools.

The name topaz has been used for any yellowish gemstones for at least two thousand years. Gem traders did not know that these yellowish stones were actually different minerals until about two hundred years ago. Gem traders recognized that quartz, beryl, corundum and olivine all had yellow variants and were not true topaz and that topaz could be other colors not just yellow. In addition, the island Topazios, after which the gemstone has been named, never produced topaz, but was a source of peridot, or olivine often confused as topaz. The island is now called Zabargad Island.

With a hardness of 8 and a variety of colors, topaz is a great choice for jewelry in any style and can even make for a unique center stone in an engagement ring.

Topaz is valued as a gemstone.

The finest British topaz is found in the Cairngorm Mountains in the Central Highlands, especially at Ben a Buird, Scotland. The famous topaz rock of the Schneckenstein, in Germany, yields pale yellow crystals that were formerly cut for jewelry. Fine topaz occurs at several locations in the Urals and in Siberia, Russia, and beautiful crystals come from Takayama and Tanokamiyama in Japan. Brazil is a famous locality, the well known sherry-yellow crystals coming from Ouro Preto, Minas Gerais, where they occur in a kaolinitic matrix. In the United States fine topaz has been worked near Pikes Peak, Colorado, and in San Diego county, California. Common topaz occurs in coarse crystals at many locations.