1930's gold filled locket

I bought this locket on the internet a few moths ago, even though my boyfriend/man doesn't like it at all.
Usually we have a bit the same taste about clothing, furniture, paintings, houses...
But I am a sucker for all sorts of lockets and he doesn't like most lockets at all. He loves fancy, stylish objects with a distinctive design.
And he thinks I have way to much jewelry already! (And he is right about that!)
So when I bought a fancy 14 carat gold locket on ebay and I saw this locket for sale from the same seller, I grabbed my chance and I bought both of them.
After all, you can't agree on everything. That would be so boring.
So I think this locket dates from the '20s or '30s. Its base metal with a gold plating. It has one small blue stone. Could be facetted glass and it has the original glass covers and paper still inside.
Hope you like it!