Polymetal
In chemistry or mining, polymetal or polymetallic is a substance composed of a combination of different metals. When the substance contains only two metals the term "bimetal" ("bimetallic") is sometimes preferred. A ' (or ) is an ore that is the source of more than one metal suitable for recovery. A mine containing polymetallic ore is a '. Concretions of manganese and iron (and other metals) found on the ocean floor are called s. They are sometimes called "manganese nodules", after their principal component.