Mica
Mineral (K,Na,Ca)(Al,Mg,Fe,Li)2-3(Si,Al)4O10(OH,F)2
Take care.
- Fragile: Handle it gently and pack it well; it breaks or crumbles easily.
About it
Group name for minerals that peel into thin, flexible, springy sheets with one perfect cleavage. Muscovite, biotite, phlogopite, and lepidolite are listed separately.
- Type
- Mineral
- Group
- Silicate (phyllosilicate), mica group
- Formula
- (K,Na,Ca)(Al,Mg,Fe,Li)2-3(Si,Al)4O10(OH,F)2
- Hardness (Mohs)
- 2–3
- Specific gravity
- 2.7–3.3
- Streak
- white
- Lustre
- vitreous (glassy), pearly
- Crystal system
- Monoclinic
- Colours
- colourless, silver, brown, black, green, pink, lilac
- Transparency
- transparent, translucent, opaque
- Cleavage and fracture
- perfect in one direction, flexible elastic sheets
Typical values: real specimens vary. For more, see mindat.org.