The majority of Black Onyx on the market today is treated in some way to enhance its colour. Enhancement of the Onyx colour has been known since ancient times, with some form of dyeing being the most common. However, when Onyx is treated, its colour and its banding are altered and it can lose the natural richness created by nature. I included a gallery below with some of the Onyx beads I have (or had, if they are sold) that exhibit the amazing rich colour of Sardonyx and the characteristic banding and stone texture of a natural, untreated Onyx when viewed under a strong light.