VTG Sterling Silver 925 Joy-Mex Hencho En Mexico Faux Turquoise Filigree Brooch

Vintage Sterling Silver 925 Signed Joy-Mex Hencho En Mexico Plata Faux Turquoise Round Filigree Brooch Pendant Measures Approximately: 2.30" Diameter Faux Turquoise measures: 1.08" Diameter Weight: 18.41grams Front of brooch/pendant in very good preowned condition, back plate has some discoloration I could not remove with polishing cloth. Front of brooch acid tested confirmed 925 sterling silver, on back of brooch Pendant bail and pin back is not testing as sterling, but is non magnetic possibly Alpaca Silver. Back plate unable to be scratch tested without damaging the filigree, but is non magnetic.