9ct gold ring with 15 stamped on the inside

by emma
(england)

I have a gold ring with 21 clear stones. It has a diamond shape with 15 stones going around the diamond then a gold diamond in the middle with another 4 stones in the shape of a diamond. It then has a stone each side. Unable to take a picture as the ring is too sparkly.

Ring was passed down to me by my mom a few months ago. I'm uncertain to whether the stones are diamond as there are 21 of them, very small. It does look as though they are, i don't know what the 15 is stamped on the inside for

15 stamped on the inside by itself, then it has CL&S and 375, unable to clearly see other 2 markings

15 is by itself then the other markings are in view roughly 3mm apart