Vintage Silver Plated Oval Stone Brooch Moonstone? Opal? 1.75” C Catch

Vintage silver plated and stone brooch Not sure what the stone is, but looks like moonstone or opal Pin on back looks to be early 1900s, but unsure about the hinge age 1.75” long In very good pre owned condition Smoke free pet friendly home Would look SO GOOD with a dark color top!!