Bì (璧, "carved jade-disk with a round hole in center") is an ancient Chinese artifact, dating back to the Liangzhu culture (3400–2250 BCE). "Bi" signified heavenly kingship in Zhou times, and were "often used ceremonially as symbolic of a covenant or guarantee, as between persons, states, heaven and a dynastic house, etc." In addition to denoting "ceremonial stone disks, usually of jadeite, or similar-looking gemstones", the word can also be used more loosely referring to "jade in general". "Bì" < Old Chinese *"pi̯ɒk" (璧) originally named "a flat stone ring", but the word was also used interchangeably with "pì" < *"pi̯äk" (), "dark blue-green stone" and sometimes "luminescent blue-green stone" probably "chlorophane".