Onyx primarily refers to the parallel banded variety of chalcedony, a silicate mineral. Agate and onyx are both varieties of layered chalcedony that differ only in the form of the bands: agate has curved bands and onyx has parallel bands. The colors of its bands range from black to almost every color.

Due to the nature of the Onyx stone, size and pattern of the bowls will vary. These Onyx Bowls measure to be approximately 6.8 inches long.