Topaz
Mineral Al2SiO4(F,OH)2
Also called Precious topaz
Take care.
- Fades or changes in light: Keep it in the dark, out of sunlight and bright display lights.
About it
Hard, heavy prisms with a diamond-shaped cross-section and one perfect cleavage across their length; Ouro Preto, Brazil, Utah's Thomas Range, and the Urals. Brown topaz often fades in sunlight.
- Type
- Mineral
- Group
- Silicate (nesosilicate), topaz group
- Formula
- Al2SiO4(F,OH)2
- Hardness (Mohs)
- 8
- Specific gravity
- 3.49–3.57
- Streak
- white
- Lustre
- vitreous (glassy)
- Crystal system
- Orthorhombic
- Colours
- colourless, blue, yellow, brown, sherry, pink, orange
- Transparency
- transparent, translucent
- Cleavage and fracture
- perfect basal
Typical values: real specimens vary. For more, see mindat.org.