See the Esther 1:6 note. The “crown” was not a crown like the king’s, but a mere golden band or coronet.
A garment - Or, “an inner robe.” The tunic or inner robe of the king was of purple, striped with white.
Related Commentaries of Esther 8:15
Esther 8:15
15 And Mordecai went out from the presence of the king in royal apparel of bluee and white, and with a great crown of gold, and with a garment of fine linen and purple: and the city of Shushan rejoiced and was glad.