Wiklundite is a rare and complex arsenate arsenite-silicate mineral with the chemical formula Pb2(Mn2+,Zn)3(Fe3+,Mn2+)2(Mn2+,Mg)19(As3+O3)2(Si,As5+O4)6(OH)18Cl6. The mineral characterizes in a large c unit cell parameter. It was found in Långban, Sweden - a home for many rare and exotic minerals.