Composition: Cu5(AsO4)2(OH)4
Crystal System : Monoclinic
Colours: Green, emerald-green
Lustre : Sub-Vitreous, resinous, waxy, greasy
Hardness (H) : 4.5
Specific Gravity (S.G) : 4.17
References: Gebhard (1999)


Extremely rare.


  • Supergene

Paragenetic and General Notes

Gebhard (1999) reports that the only known specimen of cornwallite (with malachite and bayldonite, on quartz), is held at the Hamburg Museum, in Germany. However, a specimen of cornwallite (XRD-verified) with olivenite in the collection of Gerhard Brandstetter is figured on (photo i.d. 578840).