Roeblingite

General Information: Chemical Formula:Pb2Ca6(Si6O18)(SO4)2(OH)2·4(H2O) Composition:(Molecular Weight = 1,409.57 gm)Calcium 17.06 % CaSilicon 11.95 % SiHydrogen 0.72 % H Lead 29.40 % PbSulfur 4.55 % S Oxygen 36.32 % O  Empirical Formula: Pb2Ca6Si6O18(SO4)2(OH)2·4(H2O) Locality:Franklin, Sussex Co., New Jersey, USA. Name Origin:Named after Washington A. Roebling (1837-1926), well known mineral collector and builder of the Brooklyn Bridge.Physical Properties: Cleavage:[001] Perfect, [100] Indistinct Color:white or pink. Density:3.43 Diaphaniety:Transparent to translucent Habits:Massive - Fibrous - Distinctly fibrous fine-grained forms., , Hardness:3 - Calcite Luminescence:Non-fluorescent. Luster:Vitreous (Glassy) Streak:whiteMore details...

Pb2Ca6Mn(Si6O18)(SO4)2(OH)2 4(H2O)