Hyalophane
Mineral (K,Ba)Al(Si,Al)3O8
About it
Barium-bearing potassium feldspar, heavier than orthoclase; superb clear crystals come from Busovača, Bosnia, and the Lengenbach quarry in Switzerland.
- Type
- Mineral
- Group
- Silicate (tectosilicate), feldspar group
- Formula
- (K,Ba)Al(Si,Al)3O8
- Hardness (Mohs)
- 6–6.5
- Specific gravity
- 2.58–2.82
- Streak
- white
- Lustre
- vitreous (glassy)
- Crystal system
- Monoclinic
- Colours
- colourless, white, yellowish, pink
- Transparency
- transparent, translucent
- Cleavage and fracture
- perfect and good in two directions at 90°
Typical values: real specimens vary. For more, see mindat.org.