Vintage navette stone (glass) brooch -gold tone jewelry

Brooch is in good condition and kept in a clean smoke free home. Flaws: the tip of the pin has discoloration as shown in last photo. The gold plating is off on the tip and it feels rough. It does not effect the use. It fits into the slot and closes properly. Navette stones are glass I believe. It registered as glass on my presidium II. Alternates approximate 12mm X 8mm translucent purple and lavender pieces in prong setting. Gold tone plating. No markings, brand unknown. Brooch is 2 7/8” #brooch #pin #purple #vintage