Hallmarks on my gold ring

by Elle
(Canada)

I'm not even sure if its antique or not, but it was my great grandmothers and I decided to look up the markings. So far I've been able to guess at the symbols as the ring is very worn.

The maker''s mark is T.M in a rectangle, than an anchor, which I found is the Birmingham Assay Office I think, then a symbol I don't know.

It looks like a three pointed crown in either a six point star or a three point crown in a box with spikes on the top and bottom.

Then there's what I believe to be a lion with its paw raises. What makes me think it's not an antique is that there is 18k written next to it.

Would appreciate any insight into this plain old gold ring, thanks :)