Antique Gold Filled Or Gold Shell Purple Stone? Glass Small Ornate Pin

The tiny stone or glass accent in middle looks to be a dark purple im not sure if it is glass or real semi precious gemstone either way it is a very cute little pin great detail on this one does have some metal wear more so to the back but this can be expected with vintage or antique items of any kind. Looks to be some writing on the c-clasp part of pin on back I can’t make it out This is either gold filled or gold shell Does not come with box it is for display only Important note: please refer to the photo with the measurements as some photos are enlarged to show detail