The material from Kopec, Czech Republic, has about equal Fe and Al, but the amount of Al in jarosite is usually small.
Bevdantitova podskupina ima splošo formulo AB3(XO4)(SO4)(OH)6, krandalitova AB3(TO4)2(OH)5.H2O in florencitova AB3(TO4)2(OH)5 ali 6.