Tin (Sn) is a non toxic metal that is easily recyclable and has several useful characteristics, some of them being a low melting point, malleability, resistance to corrosion and fatigue, and the ability to alloy with other metals. Tin is used in the production of tinplate (steel coated with tin) used for food packaging, as an alloy for bearing metal and also as an alloy in metallic coatings. A modern and comprehensive document on the subject is the second edition of the classic CORROSION BASICS textbook.
The role of tin as an alloy with lead in solder is in increasing due to lead's environmental hazard. Tin is also used as an alloy for bearing metal and also as an alloy in metallic coatings. The most important tin ore is Cassiterite (SnO2), although small amounts of tin are recovered from sulfide minerals such as stannite (Cu2FeSnS4). Tin occurs in both primary (typically acid igneous intrusive rocks) and secondary deposits such as alluvial and eluvial deposits. China, Peru and Indonesia are the world's major tin producers. (Internet reference 13)