This sample of hodgkinsonite is displayed in the Smithsonian Museum of Natural History. Hodgkinsonite is a silicate mineral of zinc and manganese with the composition Zn2MnSiO4(OH)2. The sample at left is about 20 cm across and is from Franklin, New Jersey. It is described as hodgkinsonite with barite. The hodgkinsonite is the pink to violet crystal part.