Elusive Man with Beard, Mid-Century Oil Painting

To me, there is something so right about this elusive portrait, painted by an artist unknown to me, but which I know dates to the 1960s or so. Thinly painted on what I believe is an unprimed linen panel/board, it seems to me both about the materiality and constructed/illusory nature of painting itself and also about the subject himself, doubly veiled in a sense--by the painter's treatment, and by his great beard! Hovering in a sort of liminal space, it/he keeps me looking at him again and again and again.

10 7/8” x 8 3/8” and in very good condition. As found, in an unremarkable vintage frame, which I think one could take or leave. I've shot in a few different lighting conditions as the colors are as elusive as he is!