Diameter of the faceted beads of black Onyx (gef.) about 16mm, length of the onyx strand about 40cm.
The name Onyx is derived from the Greek word "onyx" for "nail"; presumably this name, which has been in use for many centuries, refers to the surface of the polished stone, which is reminiscent of shiny fingernails. Spellings like onix or onyk are therefore not correct.