Interesting photo, was this the stone ginger beer jar that was found in Mounts Bay? I do not understand the reference to tin and copper, does anyone know? Fish and ice, yes, but copper and ice, tin and ice?
"Pysk, sten ha cober" (Fish, tin & copper) was a traditional toast, especially in the mining industry (often used at shareholders' dinners, etc); I think the words may have been stamped on the bottle as a motto.