Chalcophyllite
Mineral Cu18Al2(AsO4)4(SO4)3(OH)24·36H2O
Also called Copper mica
Take care.
- Contains arsenic: Wash your hands after handling it, don't make dust, and never heat it.
About it
Thin emerald to bluish-green hexagonal plates with a pearly cleavage, like a green mica. A classic from Cornwall; also from Bisbee in Arizona and Tsumeb in Namibia.
- Type
- Mineral
- Group
- Arsenate
- Formula
- Cu18Al2(AsO4)4(SO4)3(OH)24·36H2O
- Hardness (Mohs)
- 2
- Specific gravity
- 2.67–2.69
- Streak
- pale green
- Lustre
- vitreous (glassy), pearly
- Crystal system
- Trigonal
- Colours
- emerald green, bluish green, turquoise blue
- Transparency
- transparent, translucent
- Cleavage and fracture
- perfect basal, giving thin flakes
Typical values: real specimens vary. For more, see mindat.org.