Amphibole
Mineral (Na,K)0-1(Ca,Na,Mg,Fe)2(Mg,Fe,Al)5(Si,Al)8O22(OH,F)2
Take care.
- Can shed asbestos fibres: Keep it in a closed box, and never break, saw, sand, or scrape it.
About it
Group name for long prisms and fibres with two cleavages at 56 and 124 degrees; some fibrous members are asbestos. Hornblende, tremolite, actinolite, and others are listed separately.
- Type
- Mineral
- Group
- Silicate (inosilicate), amphibole group
- Formula
- (Na,K)0-1(Ca,Na,Mg,Fe)2(Mg,Fe,Al)5(Si,Al)8O22(OH,F)2
- Hardness (Mohs)
- 5–6
- Specific gravity
- 2.9–3.5
- Streak
- white to greyish green
- Lustre
- vitreous (glassy), silky
- Colours
- black, green, brown, white, grey, blue
- Transparency
- transparent, translucent, opaque
- Cleavage and fracture
- perfect in two directions at about 56° and 124°
Typical values: real specimens vary. For more, see mindat.org.