Verified October 2018
Zn2Fe3+4(SO4)4(C2O4)2(OH)4 · 17H2O
Found "near Marble Canyon". Named in honor of long term Arizona field collector Malcolm Alter. The 23rd oxalate species, first natural Zn oxalate mineral to date. Second natural Fe-Zn-S-C mineral, and fourth double salt of oxalic and another acid. Source: Mindat.