Gyrolite
Mineral NaCa16(Si23Al)O60(OH)8·14H2O
About it
Small spheres and rosettes of thin pearly plates in basalt cavities, often coated by or enclosed in apophyllite; plentiful in quarries around Mumbai and Pune, India.
- Type
- Mineral
- Group
- Silicate (phyllosilicate), gyrolite group
- Formula
- NaCa16(Si23Al)O60(OH)8·14H2O
- Hardness (Mohs)
- 3–4
- Specific gravity
- 2.38–2.4
- Streak
- white
- Lustre
- vitreous (glassy), pearly
- Crystal system
- Triclinic
- Colours
- white, colourless, tan, pale green, brown
- Transparency
- transparent, translucent
- Cleavage and fracture
- perfect in one direction
Typical values: real specimens vary. For more, see mindat.org.