Kyanite
Mineral Al2SiO5
Also called Disthene and Cyanite
About it
Long blue blades that a knife scratches along their length but not across them; Brazil, Nepal, and Tanzania (orange) give gem crystals, and it is common in schist.
- Type
- Mineral
- Group
- Silicate (nesosilicate), kyanite group
- Formula
- Al2SiO5
- Hardness (Mohs)
- 4.5–7
- Specific gravity
- 3.53–3.65
- Streak
- white
- Lustre
- vitreous (glassy), pearly
- Crystal system
- Triclinic
- Colours
- blue, green, white, grey, black, orange
- Transparency
- transparent, translucent
- Cleavage and fracture
- perfect in one direction, good in another
Typical values: real specimens vary. For more, see mindat.org.