Help, does anybody recognize this kind of stamp?

[Blissfulmess]

I have this small unidentified ring with supposedly a ruby as a center stone and some diamonds on the side. It is clearly stamped 18K, but then it has some letters "AGL 5" or "ASL 5" or something? And I just noticed that there is also "255" on it, which looks very thin, almost like scratches. The stones are all small, so I don't think I have anything of real value here, but I've never seen these kinds of stamps before. Does anybody recognize these?

 

[toomuchB]

Welcome. This question is more likely to be answered in the antique & vintage jewellery section.
I sent a request to the mods to move this thread there. Good luck!