Topaz
Image: Didier Descouens (CC BY 3.0)
Mineral NameTopaz
Chemical FormulaAl₂SiO₄(F,OH)₂
Mohs Hardness8
Crystal Systemorthorhombic
Lustervitreous
Streak Colorwhite
Cleavageperfect basal (one direction)
Fractureconchoidal
Specific Gravity3.49
Colorspink, colorless, yellow, blue, brown, green, red
Transparencytransparent
Type LocalityShigar Valley, Skardu District, Baltistan, Northern Areas, Pakistan
Mineral GroupSilicates
Usesjewelry, collector, abrasives
Associated Mineralsquartz, feldspar, muscovite, beryl, tourmaline
Rarityuncommon
Description
This specimen features a well-formed, transparent to translucent, pale pink prismatic topaz crystal, exhibiting distinct crystal faces, partially embedded in a matrix of white, granular associated minerals.
Geological Context
Topaz typically forms in igneous rocks, particularly granite pegmatites and rhyolites, and in high-temperature hydrothermal veins. It crystallizes from fluorine-rich vapors during the late stages of magmatic differentiation.
