What the "diadem" of the Jews was we know not. That of other nations of antiquity was a fillet of silk, two inches broad, bound round the head and tied behind. Its invention is attributed to Liber. Its color was generally white, sometimes, however, it was of blue, like that of Darius; and it was sown with pearls or other gems, ( Zechariah 9:16 ) and enriched with gold. ( Revelation 9:7 ) It was peculiarly the mark of Oriental sovereigns. In ( Esther 1:11 ; 2:17 ) we have cether for the turban worn by the Persian king, queen or other eminent persons to whom it was conceded as a special favor. The diadem of the king differed from that of others in having an erect triangular peak. The words in ( Ezekiel 23:15 ) mean long and flowing turbans of gorgeous colors. [CROWN] [E] indicates this entry was also found in Easton's Bible Dictionary
Bibliography InformationSmith, William, Dr. "Entry for 'Diadem'". "Smith's Bible Dictionary".