Secret Masonic Hallmark?

by Bill
(Pendleton, Oregon)

Greetings - thanks for making this forum available. I have a plain gold band ring of undetermined origin. It has a masonic hallmark and what appears to be a capitol "Z" inside a square. Any ideas here? The ring is actually a gold color rather than the copper hue that appears in the photo. There is some tarnishing that makes me think it has a lower gold content. Thanks!