Our two (OK, three) cents? Every stamp should be a steel stamp. But if we have to settle for one, this 1957 gem "steels" our heart. American Philatelist, a stamp-collecting journal, features the "America and Steel Growing Together" steel centennial stamp in its January issue.
At the 65th annual general meeting of the American Iron and Steel Institute (AISI) in 1957, the U.S. Post Office Department issued the three-cent stamp commemorating the centennial of the steel industry in America. In 1957, 85% of U.S. manufactured goods contained steel and 40% of wage earners directly or indirectly owed their livelihood to steel, according to the American Philatelist article.
Check out the history of the steel centennial stamp here. (via AISI)