.43" Topaz Crystal - Shigar Valley, Pakistan

Topaz is a rare silicate mineral that is also considered to be a semi-precious gemstone. It occurs naturally in a wide range of colors, but most natural topaz is colorless to light yellow. Topaz has a hardness of 8 on the Mohs hardness scale: diamonds, corundum, and chrysoberyl the are the only harder commonly known minerals.

It primarily forms crystals within veins and voids of volcanic rocks. The crystals grow during the later stages of magma cooling while degassing releases the fluorine required for crystal formation. Topaz crystals are either mined from inside these voids in pegmatites or collected after they have eroded out of the rock.

Most topaz is light sensitive and can fade in color if exposed to direct sunlight for too long.