The meaning of this unusual late 19th century pendant cross is at first unclear, and had not been worked out by the dealer I bought it from. From my grammar school education, I knew that Rex,Lex,Lux,Dux is Latin, and can be taken to have a Christian meaning 'My King, My Law, My Light, My Leader' and appears in various arrangements of the words as the motto of several American colleges - Yale, Talladega College, Alabama, Idaho College, and The Order of St Luke the Physician. Whatever the arrangement of the words, they centre on 'X' the Greek 'Chi' the first letter of Christ's name in Greek. The cross tests as 15ct, and is in cloisonnée dark blue and mottled white enamel. The back is completely plain. The cross is just over 1 1/4 inch:33 mm across the arms.