Sunburst Mark or What on Vintage Costume Brooch?

by Aleea
(Montana)

Hello, I have a brooch with an incised mark on the back, inside a circle, which appears to be, perhaps, sunburst rays. I was hoping you could enlighten me as to who/what this mark is. The brooch is 2" across the back, weighs 1.5 oz, and is very tightly/well made, with dozens and dozens of elements to the whole piece. In advance, thank you for any and all information you might provide. A