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A rock I found at the beach where we harvest mussels.
Don't know how old it is but it must be a few million years at least...although the area is volcanic so may be less?
It has strange markings on it which may be of human origin but not sure of its true story...it is shaped in a roughly adze/axe head shape.
I guess the mussels and Paua (abalone) at that beach have been harvested for many years before we found them!