By far the most ancient with the August birthstones, sardonyx is a mix of two forms of chalcedony (cryptocrystalline quartz): sard and onyx. Bands of brownish crimson to brown to darkish orange sard alternate with generally white or black layers of onyx. While there are several chances to rejoice this https://www.gemsbiz.com/blog/explore/birthstones-by-zodiac-sign