is a basic hydrous potassium iron sulfate with formula KFe3+3(SO4)2(OH)6 and hardness of 2.5-3.5.
Jarosite is both an individual mineral, as well a group name of several similar minerals. Jarosite is the most common member of the group; some of the other rare members include Ammoniojarosite, Argentojarosite, Beaverite, Dorallcharite, Hydroniumjarosite, Natrojarosite, and Plumbojarosite.Jarosite was first described in 1852 by German mineralogist August Breithaupt in type locality of Barranco Jaroso in the Sierra Almagrera in Southern Spain. In 2004, it was detected by the exploration rover Opportunity on Mars, indicating the possible presence of water that once existed on Mars.It comes from Bennachia,Inverurie,Aberdeenshire, Scotland.
Size: 9.8x7.3x4.4 mm.
Weight: 1.65 ct.