Meaning of ring with seven spikes

I found this symbol on the stained glass of a Catholic church: What does it mean or represent? There's nothing else around this symbol, just what's in the image. To me, it looks like either a ring with seven spikes on both sides or some sort of crown, but I couldn't find anything about this symbol online. I feel like I have seen/read this symbol before, but I can't pinpoint it. Initially, I thought it might have been Jesus' crown of thorns, but it looks like this ring/crown is made of gold, not thorns.