Vintage Amethyst and Sterling Screw Backs circa 1920s

Stunning vintage amethyst and sterling screw-back earrings, circa 1920. I bought these from a vintage shop 20 years ago and have never worn them. I considered converting them for pierced ears, but did not any to alter from original state and depress their value. One thing to note is the dangling part is delicate and they can separate. A professional jeweler can close the loop or you can solder them, which may depress the value. Please ask any questions.