Metallurgy is the study of the properties, and techniques for working, metallic elements, and their alloys.
In classical times seven metals were recognized: Iron, Gold, Silver, Tin, Copper, Lead and Mercury. Refining and working with each different metal required different skills.
With the development of modern chemistry an additional 87 chemical elements have been found on planet Earth. Most have chemical properties, like good electrical and thermal conductivity, that classify them among the metals. Metals, in their solid form, form small crystals.