Onyx is a variety of Agate.

In correct usage, the name refers to a black and white banded variety of Agate, or sometimes a monochromatic Agate with dark and light bands (brown and white for example) - but traditionally the name was reserved for black and white banded Agate, and brown varieties named Sardonyx.

 
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* Photos show all sides.
* Sizes, shapes and colors my vary due to being a natural stone, being hand-carved and/or difference in computer monitors.