This piece stumped me when I found it. The red crystals reminded me of the highly collectible garnet cluster necklaces from the early 1900s. I believe this necklace was made to celebrate that style at a more affordable price point. All of the red glass pieces are individually prong set in the pendant. This is a longer than usual necklace from that era at 20 inches. I am happy to shorten this piece if you prefer a shorter length!

Rare Vintage Red Crystal Prong Set Teardrop Pendant Necklace