Topaz
Species
Uncommon · Al₂SiO₄(F,OH)₂
Aluminium silicate fluoride found primarily in granitic pegmatites. Its perfect basal cleavage makes it prone to splitting along flat planes parallel to the base. Imperial topaz, orange to pink or red, is the most prized variety, and red and pink crystals are rare.
Identity
- Formula
- Al₂SiO₄(F,OH)₂
- Chemical class
- Silicate
- Also known as
- Imperial topaz (golden-orange), Blue topaz
- Used in alchemy
- Topaz Powder
Crystallography
- Crystal system
- Orthorhombic
- Habits
- Prismatic, Columnar
- Fracture
- Subconchoidal
Physical properties
- Mohs hardness
- 8
- Density
- 3.57 g/cm³
- Luster
- Vitreous
- Colors
- colorless, blue, yellow, pink, orange, brown
- Streak
- white
- Transparency
- Transparent, Translucent
Geology
- Origins
- Igneous, Hydrothermal, Metamorphic
- Host rocks
- Granite, Volcanic rock
- Associated minerals
- Quartz, Beryl, Tourmaline, Fluorite
- Found in
- Pegmatite deposit
- Geography
- Brazil, Pakistan, Russia, USA, Sri Lanka
Classification
- Rarity
- Uncommon
- Gem quality
- Yes
Sources
- M. Pasero and others, IMA Commission on New Minerals, Nomenclature and Classification, The New IMA List of Minerals, updated September 2026. International Mineralogical Association (CNMNC), 2026.
- Topaz. Mindat.org (Hudson Institute of Mineralogy).
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Topaz. Mineral Data Publishing, Handbook of Mineralogy, 2001.
- Topaz. Gemdat.org (Hudson Institute of Mineralogy).
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