Size of blue chalcedony about 24 x 12mm
The terms "Calchedon" and "Carchedon" are found for the first time in Pliny the Elder in his Latin Naturalis Historia in the 1st century AD. Which stones have been described here, however, cannot be clearly identified on the basis of the descriptions. Over "intermediate stages" like Calcedon, Calzedon, Chalzedon or Kalcedon the name changed to the today common Chalcedon.