Japanned vintage green rhinestone brooch (unsigned)

Here's a green rhinestone brooch I bought a few months ago--yielding to temptation as green is my favourite colour. It features two types of rhinestones, foiled and unfoiled. Both are peridot greens of similar hues, depending on light and background. The japanned setting adds extra intensity.
On a whim I put the brooch under blacklight and discovered the foiled stones are made of uranium glass. That suggests it dates from the 1950s or thereabouts. However, there's no mark or signature whatsoever. The maker is a mystery!