This sterling silver counter is in the form of a driguk, or curved knife (Tib. གྲི་གུག་, driguk, Wyl. gri gug).

From Deity, Mantra, and Wisdom:

“The curved knife is a symbolic implement that symbolizes the severing of the four demons.”

Bhum, pronounced “boom,” is the Tibetan term for 100,000. Bhum counters are used with a mala to mark large accumulations of mantra recitations. They can be clipped onto the mala and moved bead by bead to track thousands or hundreds of thousands of mantra, either on their own or together with a pair of standard counters.

Length: 1¾” (45 mm) including clip”
Width: 3/4” (19 mm)