The most historical on the August birthstones, sardonyx is a mix of two kinds of chalcedony (cryptocrystalline quartz): sard and onyx. Bands of brownish red to brown to dim orange sard alternate with ordinarily white or black layers of onyx. You can also use Pisces birthstone in earrings and rings. https://www.gemsbiz.com/blog/explore/birthstones-by-zodiac-sign