A jewel on thy forehead; better, with the Revised Version, a ring upon thy nose. The word has the same meaning in Genesis 24:47 ("earring" in the Authorized Version); Isaiah 3:21 (where the Authorized Version gives "nose jewels"); Proverbs 11:22.
Jerome, however, notes (in loc.) that the Syrian women of his time wore pendants or lockets that hung from the forehead to the nostrils. The crown, or diadem (LXX; στέφανος καυχήσεως), the thin circlet of gold confining the hair, completed the catalogue of ornaments.
The Chaldee Targum continues its spiritual interpretation: "I gave the ark of my covenant to be among you, and the cloud of my glory overshadowed you, and the angel of my presence led you in the way."
And, if we assume, as we legitimately may assume, that Ezekiel, above all others, the prophet of symbolism, did not fill up his picture with details which were only meant to fill it up, this seems a not unfitting interpretation.