The ancient diadem was the highly adorned and richly gemmed head-dress, worn by kings. In the east the diadem was a symbol of absolute power.
The diadem was usually a headband about two inches wide, tied in the back and made of silk, and inlaid with gold and the most precious gems. The crown was a symbol of glory, and the diadem was a symbol of beauty.
"In that day shall the LORD of hosts be for a crown of glory, and for a diadem of beauty, unto the residue of his people" - Isaiah 28-5
"For Zion's sake will I not hold my peace, and for Jerusalem's sake I will not rest, until the righteousness thereof go forth as brightness, and the salvation thereof as a lamp that burneth. And the Gentiles shall see thy righteousness, and all kings thy glory: and thou shalt be called by a new name, which the mouth of the LORD shall name. Thou shalt also be a crown of glory in the hand of the LORD, and a royal diadem in the hand of thy God. Thou shalt no more be termed Forsaken; neither shall thy land any more be termed Desolate: but thou shalt be called Hephzibah, and thy land Beulah: for the LORD delighteth in thee, and thy land shall be married. For as a young man marrieth a virgin, so shall thy sons marry thee: and as the bridegroom rejoiceth over the bride, so shall thy God rejoice over thee." - Isaiah 62:1-5
"And thou, profane wicked prince of Israel, whose day is come, when iniquity shall have an end, Thus saith the Lord GOD; Remove the diadem, and take off the crown: this shall not be the same: exalt him that is low, and abase him that is high. I will overturn, overturn, overturn, it: and it shall be no more, until he come whose right it is; and I will give it him." - Ezekiel 21:25-27
"I put on righteousness, and it clothed me: my judgment was as a robe and a diadem." - Job 29:14
"The God who made the world and all things in it, since He is Lord of heaven and earth, does not dwell in temples made with hands; nor is He served by human hands, as though He needed anything, since He Himself gives to all people life and breath and all things; and He made from one man every nation of mankind to live on all the face of the earth, having determined their appointed times and the boundaries of their habitation, that they would seek God, if perhaps they might grope for Him and find Him, though He is not far from each one of us; for in Him we live and move and exist, as even some of your own poets have said, `For we also are His children." - Acts 17:24-28
Isaiah 62:3 - Thou shalt also be a crown of glory in the hand of the LORD, and a royal diadem in the hand of thy God.
Isaiah 28:5 - In that day shall the LORD of hosts be for a crown of glory, and for a diadem of beauty, unto the residue of his people,
Ezekiel 21:26 - Thus saith the Lord GOD; Remove the diadem, and take off the crown: this [shall] not [be] the same: exalt [him that is] low, and abase [him that is] high.
Job 29:14 - I put on righteousness, and it clothed me: my judgment [was] as a robe and a diadem.