The ichthys or ichthus, from the Greek ikhthū́s is a symbol consisting of two intersecting arcs, the ends of the right side extending beyond the meeting point so as to resemble the profile of a fish. It has been speculated that the symbol was adopted by early Christians as a secret symbol; a shibboleth to determine if another was indeed Christian.[2][3] It is now known colloquially as the "Jesus fish". Wikipedia. Lovely, shiny and detailed. I believe it may be sterling silver or stainless steel as I have had it for 20 years and it has never tarnished.