Classified As

Connects a material to the class it belongs to, one of the eleven material class subcategories such as Igneous Rocks, Silicate Minerals or Phosphate Minerals. The inverse reading, Classifies, names the same relationship from the class toward each material in it. This relation type gives the classification already recorded as an enum fact on each material a durable, comparable entity identity; it does not replace that enum fact, which keeps classifying every material exactly as before.