Hydroxyapophyllite-(K)
Mineral KCa4Si8O20(OH,F)·8H2O
Also called Hydroxyapophyllite and Apophyllite
About it
The hydroxyl-rich apophyllite, identical to the eye to fluorapophyllite and told apart only by analysis; it occurs in basalt cavities and skarns.
- Type
- Mineral
- Group
- Silicate (phyllosilicate), apophyllite group
- Formula
- KCa4Si8O20(OH,F)·8H2O
- Hardness (Mohs)
- 4.5–5
- Specific gravity
- 2.33–2.37
- Streak
- white
- Lustre
- vitreous (glassy), pearly
- Crystal system
- Tetragonal
- Colours
- colourless, white
- Transparency
- transparent, translucent
- Cleavage and fracture
- perfect in one direction (basal)
Typical values: real specimens vary. For more, see mindat.org.