Cyanotrichite
Mineral Cu4Al2(SO4)(OH)12·2H2O
Also called Lettsomite and Velvet copper ore
Take care.
- Fragile: Handle it gently and pack it well; it breaks or crumbles easily.
About it
Velvety sky-blue tufts and sprays of tiny needles, often on limonite, in oxidized copper deposits. Fine specimens come from Bisbee in Arizona, Lavrion in Greece, and the Grandview mine in the Grand Canyon.
- Type
- Mineral
- Group
- Sulfate, basic copper-aluminum sulfate
- Formula
- Cu4Al2(SO4)(OH)12·2H2O
- Hardness (Mohs)
- 1–3
- Specific gravity
- 2.74–2.95
- Streak
- pale blue
- Lustre
- silky
- Colours
- sky blue, azure blue
- Transparency
- translucent
- Cleavage and fracture
- none seen; velvety tufts of fine needles
Typical values: real specimens vary. For more, see mindat.org.