| Juansilvaite | |
| Category: | Arsenate, Sulfate |
| Formula: | Na5Al3[AsO<sub>3</sub>(OH)]4[AsO<sub>2</sub>(OH)<sub>2</sub>]2(SO4)2·4H2O |
| Imasymbol: | Jsl[1] |
| System: | Monoclinic |
| Class: | Prismatic (2/m) (same H-M symbol) |
| Symmetry: | C2/c |
| Unit Cell: | a = 18.18, b = 8.63 c = 18.51 [Å], β = 90.39° (approximated) |
Juansilvaite is a very rare,[2] complex arsenate-sulfate mineral with formula Na5Al3[AsO<sub>3</sub>(OH)]4[AsO<sub>2</sub>(OH)<sub>2</sub>]2(SO4)2·4H2O.[3] It is both hydroxyarsenate and dihydroxyarsenate. It is among few relatively new minerals from the Torrecillas mine in Chile, the other being torrecillasite, canutite, chongite, gajardoite, leverettite, and magnesiokoritnigite.[4] Although having quite common among minerals space group C2/c, juansilvaite has a new type of structure.