Grunerite
Mineral Fe7Si8O22(OH)2
Also called Amosite and Brown asbestos
Take care.
- Can shed asbestos fibres: Keep it in a closed box, and never break, saw, sand, or scrape it.
About it
Brown, fibrous to bladed iron amphibole of banded iron formations; its fibrous form, amosite, was mined in South Africa as brown asbestos.
- Type
- Mineral
- Group
- Silicate (inosilicate), amphibole group
- Formula
- Fe7Si8O22(OH)2
- Hardness (Mohs)
- 5–6
- Specific gravity
- 3.4–3.6
- Streak
- white
- Lustre
- silky, vitreous (glassy)
- Crystal system
- Monoclinic
- Colours
- brown, grey, greenish
- Transparency
- transparent, translucent
- Cleavage and fracture
- good in two directions at about 56° and 124°
Typical values: real specimens vary. For more, see mindat.org.