Enoch showed no surprise, but his features were locked in a rigid mask.

His features were a rigid mask of shadow and light.

When at last she raised her head, the tears were still there, but pride had set her face in a rigid mask.

He nodded his head slowly, his face a rigid mask.

He glared at her, his face a rigid mask of hard planes and sharp angles.

He trembled, shook, then felt his face become a rigid mask.

His face was an angry mask, rigid with the intensity of emotion.

The President's face became a rigid mask, as he fought for control.

Her face had set into a rigid, cold mask.

He ignored that, his features a rigid mask of concern in the shadowy light.