Topaz
A hard, heavy silicate; colourless by nature, blue by irradiation, imperial by luck.
- Family
- Topaz
- Formula
- Al₂SiO₄(F,OH)₂
- Mohs
- 8
- System
- Orthorhombic
Drag to turn
Science
Topaz grows in the last fluorine-rich stages of granite cooling, often as large clean crystals with one perfect cleavage that cutters must avoid. Chromium makes the pink and the orange-pink 'imperial'; the widespread blue is colourless topaz irradiated and heated. It is the hardest common silicate.
- Mineral
- Topaz
- Formula
- Al₂SiO₄(F,OH)₂
- Crystal system
- Orthorhombic
- Mohs hardness
- 8
- Specific gravity
- 3.53
- Refractive index
- 1.619 to 1.627
- Lustre
- Vitreous
- Colours
- Colourless, Blue, Orange, Pink, Imperial
- Birthstone
- November
Composition
Al₂SiO₄(F,OH)₂. Made of Aluminium, Silicon, Oxygen, Fluorine, Hydrogen, with trace Chromium responsible for colour.
Origin
- BrazilOuro Preto, imperial topaz
- PakistanKatlang, pink
- RussiaUrals
- Sri Lanka
- Nigeria
- Mexico
- United StatesUtah, Texas
Filled dots are primary sources
Rarity
Colourless topaz is abundant and becomes blue topaz by irradiation. Natural imperial and pink topaz are rare, from Ouro Preto and Katlang.
- 1 Abundant
- 2 Common
- 3 Uncommon
- 4 Rare
- 5 Exceptional
Hardness
Topaz sits at 8 on the Mohs scale. It will scratch glass and holds a polish in daily wear.
Energy
Associations from crystal-healing tradition, recorded here as folklore. They are not medical claims.
Chakras
- Solar Plexus
- Throat
Element
- Fire
Zodiac
- Sagittarius
- Scorpio
- Leo
Planets
- Sun
- Jupiter
Properties
- Confidence
- Joy
- Generosity
- Truth
- Good fortune
Lore
The 'Braganza diamond' in the Portuguese crown, 1,680 carats, is now believed to have been colourless topaz. The name may come from Topazios, an island in the Red Sea that actually produced peridot.
Imperial topaz was named for the Russian tsars, who reserved Ural pink topaz for the imperial family in the 19th century.
- BlueSky, Swiss and London blue are all irradiated colourless topaz.
- CleavagePerfect basal cleavage; a knock can split a stone.