Then take silver and gold, and make crowns, and set them upon the head of Joshua the son of Josedech, the high priest; Make crowns - עטרות ataroth; but seven MSS. of Kennicott's and De Rossi's, and one ancient of my own, with the Syriac and Chaldee, have עטרת atereth, a crown, or tiara. And as Joshua the high priest is alone concerned here, I think one crown only is intended.
Related Commentaries of Zechariah 6:11
Zechariah 6:11
11 Then take silver and gold, and make crowns, and set them upon the head of Joshua the son of Josedech, the high priest;