(click on pictures to enlarge)
Diamond Medal was a National Pen Products brand. This example is identical to pencils bearing a variety of different names, such as:
The next three examples are from Diamond Medal's flagship "Diplomat" line and are truly fine examples.
The next two, with their stepped AND banded tops, are about as deco as you can get.
The last two are relatively ordinary pencils. Note, however, the similarity between the example on the right and Parker Challengers of the same period.