The carving work resulting from use of a Kangaroo incisor is of fine quality.
Used on wood, workable stone and for shell cutting , these were tools used by the Elders who had an understanding of the carving of totem work on implements.
This is an unusual one, I have had a few in the past but this is very long. An ochre design and random engraved marks for thumb and forefinger position,  while the cutting edge is provided by the incisor tooth.
This implement type occurred throughout Australia.
18cm long, well used and old. A beautiful object.

REF: Australian Aboriginal Stone Implements. Prof. FD McCarthy.  
Also, Aboriginal Australia. A.D.G.C.