Sterling silver gemstone rectangular pierced earrings jewelry

Earrings are in good condition and kept in a clean smoke free home. Marked S925 on silver hook, brand unknown, and tested with a presidium II came up as gemstone. It landed on jadeite but also landed on quartz, amethyst , citrine category.. It’s definitely a gemstone but I am not a gemologist. Rectangle gemstone is 1 1/8” X 2.5/8”X 2mm #jewelry #gemstone #earrings