Just as a note, the item is religious. Its called a riza and it is used to adorn Orthodox Christian Icons. So that piece acts as the halo around the Saint.
The riza (риза) and the coronet (венец) on the icon are different elements of the frame (оклад), covering different parts of the icon. The riza is an overlay decoration covering the clothes of the saints on the icon, symbolizing their spiritual purity and grace. The coronet is a halo, an adornment around the head, symbolizing divine light and holiness. Thus, the riza covers the body and clothes, while the coronet surrounds the head, emphasizing the spiritual status and holiness of the depicted.