Clearly poor workmanship, seen mainly in the larger open background areas. Difficult to interpret clearly, possibly a resultant of several factors. Stamping on an unprepared plate and perhaps a stamp that is no longer in the best shape, and in part also probably the result of acquired characteristics. Definitely better look shielded spaces, such as, for example, the contact of the background with the relief, in the nooks and crannies of the drawing, or between the letters, where there is a fresher background surface and a clearer sheen. The border is typical, from a die-cut with a clear, fresh sheen.
A rare print in aluminum of a collector coin issued in silver.
The feature is minted with an inverted stamp - reverse 180 degrees.