What's the difference between Bolivian Melgarejo coins and medals?

Hello, I was looking through some old, silver coins from Bolivia and noticed some incoherence between the Melgarejo objects issued during the 1860s.

Some “Melgarejo” medals:
N#237965 

N#334031 

N#396082 

Some “Melgarejo” coins:

N#42613 

N#11547 

My question is, what's the difference in the determination of Melgarejo “coins” and “medals”? Why are some objects classified as medals, say, the ¼ Melgarejo (Belzu Murder), whereas some are classified as coins, like the ¼ Melgarejo (N#11547), even though they are of the same denomination?

Thanks,

Piero

The put it simply, there isn't. Bolivia was different from every other country in that their “proclamation medals” (better described as “monetary medals”) were meant to be circulated as coins (and they most definitely did). There are two different types of Melgarejo pieces, N#11547 N#47877 and N#42613 are what most people consider the traditional Melgarejo pieces and are considered by most (including Krause) as “true” coins. However, that isn't an accurate description for them, as they were meant to be payment for the army and followed the earlier sol system instead of the new decimal system that had just been rolled out (as evidenced by their lower 66.6% purity). The other Melgarejo pieces are described as the more traditional “monetary medals”  based on those other 3 melgarejo issues I mentioned before. Realistically, however, both the “coin” and the “monetary medal” melgarejos circulated together and served the same purpose (as well as the coin and monetary medals of the sol system) and should most accurately all be considered coins. I have requested this a few times but it has been rejected on the basis that medals from other countries do not follow this logic, despite the situation in Bolivia and their monetary medals being unique and well documented. If you want more information, here are two great resources: http://www.chicagocoinclub.org/projects/PiN/cdb.html https://www.jstor.org/stable/pdf/43573604.pdf