Gemstone | Crystal System | Density | Hardness | Refractive index | Treatments |
Topaz |
orthorhombic | 3.53 | 8.0 | 1.619-1.627 | blue is irradiated |
Color: Durability: Localities:
|
TopazAl2SiO4(FOH)2
Topaz is an aluminum, hydroxyl-flourine silicate. Strong chemical bonding makes it the hardest of the silicate minerals. A common misconception is that all topaz is yellow. It is most commonly colorless, but colors include blue, pale green, and the spectrum of yellow through sherry orange to pink, and most unique, red. Topaz was used in ancient Egypt and Rome, where it was imported from Ceylon (Sri Lanka). During the Middle Ages topaz was thought to strengthen the mind and prevent mental disorders as well as sudden death. It has been considered a "cooling" gem, much like ruby is considered a "hot" gem. Topaz was thought to have the ability to quickly cool boiling water and flaring tempers. |