Iban Dayak. Sarawak State, Borneo Island, Malaysia.
Wood. H: 15.75" (40 cm), W: 8" (20.3 cm), D: 5” (12.7 cm).

A rare and powerful ceremonial mask with an aggressive protective expression meant to ward off malevolent spirits.
The face of the mask has numerous areas where various materials were inserted, likely pieces of stone, teeth, bone, or minerals.
There is one piece still wedged inside a hole below the left facing eye, that is unidentified, but appears to be a piece of crystal.
One of the best Iban masks I have come across.