John Gilbert Spoon- Curious about other hallmarks

Hi! I am just curious about, what I assume is, a John Gilbert electroplated spoon…

I am assuming the “Z” represents the year (sometime in the 1800’s?) and the “A1” represents the quality. What does the inverted triangle with the cross mean? Also, there is a tiny “p” in front of the “Z”. Any clues on this would be much appreciated.

Thank you!

“A1” is, as you suggest, an indicator of plating quality. The triangle and cross symbol is Gilbert’s trade mark. There is no evidence to suggest that the “Z” is a date code. However Gilbert marks are seen with a range of additional letters so it is a possibility that they represent dates. If they are then no key to the system is known. I don’t know whether the P has any significance,


Thank you so much! I really appreciate it!