Help identifying a pendant and its hallmark

[CmartinR1982]

Hi,

I'm not sure if I'm posting this in the correct location.I have a older pendant it's not marked sterling but it tests positive and it has a really weird looking hallmark on the back and on the loop were you would put a necklace. If someone could help me identify the hallmark or point me in the right direction I would appreciate it. I attached some pictures below, thanks in advance.