50 Centimos Plata Meneses

"The largest series attributed to Mondariz is the one that features a Gothic M on one side, inside a sun whose rays form a square. The original idea of ​​identifying them with this town comes from Jaime Paz, who stated in one of his articles: 'In Orense, I was shown some coins framed in a picture that were said to belong to the Mondariz Spa.' However, Paz is doubly mistaken: first, in identifying the M as a mark of Mondariz, and second, in assuming that all the coins with this motif were used there. In reality, we are looking at the trademark registered by the Plata Meneses company to identify its work. This can be verified not only by its explicit presence in the company's catalogs and advertising since the 19th century, but also by observing the hallmarks of the pieces made in its factories or by accessing the historical information included on the company's website. Regarding the possibility that some of these coins may have been used in Mondariz, exclusively or not, this is an option we cannot [confirm]. We cannot completely rule it out, but we seriously doubt it, since the pieces identified by Paz are part of the general catalog of the aforementioned silversmiths for use "in cafes and casinos," and it seems strange that they would have been used in Mondariz when they have other series that do have a marked differentiating character of the establishment."

https://monedasgallegas.com/mondarizM.html