This character wears a tiara, a diadem or a circlet.

Tiaras and diadems are head ornaments worn by ancient men and women to denote high status.

A tiara is a jeweled, ornamental crown traditionally worn by women.
A diadem is a type of crown, specifically an ornamental headband worn by monarchs and others as a badge of royalty.
A circlet is a crown with neither arches nor a cap (internal covering).