Thomsonite
Mineral NaCa2Al5Si5O20·6H2O
Also called Thomsonite-Ca and Lintonite
About it
Radiating fibres and blocky crystals; polished nodules with pink, white, and green "eyes" come from Lake Superior's north shore in Minnesota, while crystals occur in basalt worldwide.
- Type
- Mineral
- Group
- Silicate (tectosilicate), zeolite group
- Formula
- NaCa2Al5Si5O20·6H2O
- Hardness (Mohs)
- 5–5.5
- Specific gravity
- 2.25–2.4
- Streak
- white
- Lustre
- vitreous (glassy), pearly
- Crystal system
- Orthorhombic
- Colours
- white, pink, green, red, yellow, colourless
- Transparency
- transparent, translucent
- Cleavage and fracture
- perfect in one direction
Typical values: real specimens vary. For more, see mindat.org.