Jarosite

General Information: Chemical Formula:KFe+++3(SO4)2(OH)6 Composition:(Molecular Weight = 500.81 gm)Potassium 7.81 % K Iron 33.45 % FeHydrogen 1.21 % H Sulfur 12.81 % S Oxygen 44.73 % O  Empirical Formula: KFe2+3(SO4)2(OH)6 Environment:Secondary mineral, forming under conditions of weathering in arid climates. Locality:Barranco Jaroso in southern Spain. Name Origin:Named after its locality.Physical Properties: Cleavage:[0001] Distinct Color:brown, yellow, yellow brown, or light yellow. Density:2.9 - 3.3, Average = 3.09 Diaphaniety:Translucent Habits:Crystalline - Fine - Occurs as well-formed fine sized crystals., Fibrous - Crystals made up of fibers., Massive - Uniformly indistinguishable crystals forming large masses. Hardness:2.5-3.5 - Finger Nail-Copper Penny Luminescence:None. Luster:Vitreous (Glassy) Streak:yellowMore details...

General Information: Chemical Formula:(H3O)Fe+++3(SO4)2(OH)6 Composition:(Molecular Weight = 480.74 gm)Iron 34.85 % FeHydrogen 1.89 % H Sulfur 13.34 % S Oxygen 49.92 % O  Empirical Formula: (H3O)Fe3+3(SO4)2(OH)6 IMA Status:Approved IMA 1960Physical Properties: Color:yellow, dark straw yellow, reddish brown, or brown. Density:2.496 - 2.905, Average = 2.7 Diaphaniety:Transparent to Translucent Hardness:4-4.5 - Between Fluorite and Apatite Luster:Vitreous - ResinousMore details...