A dime struck on a quarter?

Victoria S. writes: I have a quarter that has a dime head stamped over the quarter head. What is the value of this coin? I also have a double faced dollar bill. It has the presidents head on both sides. What is the value of this dollar?

A dime struck on a quarter is physically impossible considering that the quarter would be too big to fit in a press set up to strike dimes. You most likely have a dime struck INTO a quarter. This is done with two blocks of wood, a dime and a quarter. The dime is pressed into the quarter by either using a vice or a mallet. The image of the dime is impressed into the quarter. The image of the dime is retrograde (backwards).

Your “double headed” dollar note is most likely an “offset error”. Please see What’s My Paper Money Error Worth? for an explanation, prices and images of offsets and other paper money errors. There is also a simulated “error” with no part of the reverse design visible. This is created by pasting two one dollar notes together back to back.