Vintage 375 earring

Hello I’ve just been looking at some old bits that I’ve not really checked out & have just seen that this earring is actually real gold marked 375 & another mark after that I’ve not seen before, made me have a closer look at it and I noticed that all the stones seem to be in place which is a miracle considering it is ina bag of old bits.
Wondering what the stones actually are, hopefully diamonds, wondering what period it’s from as I believe going by 375 marking means it’s very old, gonna have a search for the other one