Black Onyx Jewelry: The lovely Gem Onyx, the beauty in the gems, is a type of chalcedony naturally occurring with the banded parallel layers. It was first reported in 77 A.D by Pliny the Elder and was named after the Greek word meaning "claw" or "fingernail" due to its similar resemblance. The appealing pieces of black onyx make some of the enticing black onyx jewelry giving the wearer a fascinating look.