Body tiara are a head slot item used in Runecrafting. In can be created by using a tiara on the Body rune alter with a Body Talisman. Doing this grants 37 Runecrafting exp.
The main use of the Body tiara is that it lets you enter the Body rune alter with a left click and since it can be equipped it frees up an inventory space that the Body talisman would normally occupy.