What is the significance of the golden crowns on the elders' heads?

Revelation 4:4 (ESV)

4 Around the throne were twenty-four thrones, and seated on the thrones were twenty-four elders, clothed in white garments, with golden crowns on their heads.

Persons sitting on heavenly thrones, in the presence of God himself, are royalty of the highest rank. That they wear golden crowns on their heads befits their honoured position before God’s throne and points up the greatness of the God before whom they serve. Revelation 4:10 will make clear that these crowns are not the fruit of their own labour but are gifts of grace.