gemstone

Yellow Topaz

Al2SiO4(F,OH)2

Hardness: 8.0 on Mohs scale; Color: Pale yellow to golden-brown; Luster: Vitreous; Crystal structure: Orthorhombic; Cleavage: Perfect basal cleavage; Specific Gravity: 3.49-3.57.

Hardness: 8
Color: Pale yellow to golden-brown
Luster: Vitreous

Identified July 10, 2026More gemstone →

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Physical properties

Hardness: 8.0 on Mohs scale; Color: Pale yellow to golden-brown; Luster: Vitreous; Crystal structure: Orthorhombic; Cleavage: Perfect basal cleavage; Specific Gravity: 3.49-3.57.

Formation & geological history

Formed through the reaction of fluorine-bearing vapors during the final stages of crystallization in igneous rocks like granite and rhyolite, or in pegmatites. Most deposits date from the Mesozoic to Cenozoic eras.

Uses & applications

Primarily used as a gemstone in jewelry (rings, necklaces, earrings). Historically used for carving. Industrial uses are limited compared to its ornamental value.

Geological facts

The name likely comes from Topazios, an ancient name for St. John's Island in the Red Sea. Topaz is the birthstone for November. Large crystals weighing hundreds of pounds have been found in Brazil.

Field identification & locations

Identified by its high hardness, higher specific gravity compared to quartz, and perfect cleavage plane. Commonly found in Brazil, Russia, Pakistan, and the United States (Utah/Texas).