Probably the most historical on the August birthstones, sardonyx is a mix of two sorts of chalcedony (cryptocrystalline quartz): sard and onyx. Bands of brownish pink to brown to darkish orange sard alternate with normally white or black layers of onyx. Certainly, this thirty day period is Valentine's Working day, https://www.gemsbiz.com/blog/explore/birthstones-by-zodiac-sign