irons — Chemistry. a ductile, malleable, silver-white metallic element, scarcely known in a pure condition, but much used in its crude or impure carbon-containing forms for making tools, implements, machinery, etc. Symbol: Fe; atomic weight: 55.847; atomic number: 26; specific gravity: 7.86 at 20°C. Compare cast iron, pig iron, steel, wrought iron.
steels — any of various modified forms of iron, artificially produced, having a carbon content less than that of pig iron and more than that of wrought iron, and having qualities of hardness, elasticity, and strength varying according to composition and heat treatment: generally categorized as having a high, medium, or low-carbon content.
minerals — any of a class of substances occurring in nature, usually comprising inorganic substances, as quartz or feldspar, of definite chemical composition and usually of definite crystal structure, but sometimes also including rocks formed by these substances as well as certain natural products of organic origin, as asphalt or coal.
ore — a metal-bearing mineral or rock, or a native metal, that can be mined at a profit.
