This wooden printing block has been carved elaborately with the Om Mane Padme Hum mantra in circular mandala form. The field beyond the circle is carved with flame-like scrolls which seems to suggest a fiery realm but with a Buddhistic symbol in each corner.
Such woodblocks were used to make prints usually on light cotton fabric or thin hand-made paper which was then folded into a tight bundle and then wrapped with coloured string. The bundle then served as a protective amulet that was worn and which protected the wearer against sickness and other difficulties. Some might have been stored and worn inside a ga’u box as well.
See Brauen (2009, p. 32) for a similar example in the Rubin Museum.
The example here is in fine, obviously old condition and has a marvellous dark patina.
Brauen, M., et al., Mandala: Sacred Circle in Tibetan Buddhism, Arnoldsche/Rubin Museum of Art, 2009.