I have a penny that weighs 3.12 now is that correct I have a book that l have and it says 2.5 grams from 1982 - 2009 is what they should have weighed this penny is a 1982 no Mint mark
In 1982 the Philadelphia mint ( no MM) made both bronze( 3.1) and zinc plated ( 2.5)., so no extra value. http://www.lincolncentresource.com/smalldates/1982.html
In 1982 they switched from copper to zinc towards the end of the year. It is a transitional year and 1982 contains both zinc and copper cents.
