Onyx Meaning and Healing Properties. A banded variety of Chalcedony, Onyx is cryptocrystalline, meaning it is a stone in which consists of fine inter-growths of silica minerals, Quartz and Moganite. Onyx exhibits parallel banding making it very unique in composition, as most banding is very chaotic as seen in Agate. Though normally black, Onyx does have variants such as Sardonyx, which bands appear in shades of red due to the sard inclusions altering its coloring. Artificial treatments have also been used since ancient times to produce both common Black Onyx and colored Onyx, mostly yellow or red. Onyx can be found in various regions of the world including Argentina, Australia, Brazil, Canada, China, Czech Republic, Germany, Madagascar, Pakistan, India, and various states of the U.S.