Un-struck Blanks and Planchets
A coin blank is a flat disk of metal that has not
been struck.  A coin blank is also referred to as a
planchet.  

There are two types of planchets.  Type 1 is flat,
and type 2 has upset rims.  

The images to the left are of a type 2 copper
planchet, and an type 2 uncoated zinc planchet.  
There are many types of Lincoln Cent planchets
including those intended for steel cents.