Each of the 9 Aboriginal tribes has their own design of the knife which is given to the newborn-boys as a gift to last a lifetime.
They are allowed to wear the blade at age 12. It not only is a deadly weapon, but more important, it is also a multifunctional tool.
It figured prominently in the Pacific War, a war essentially of perfecting survival skills in hell and this tool was absolutely indispensable.
There was also a spiritual bond between an Aboriginal man and his knife, not unlike that between the traditional Japanese samurai and his sword.
This collection was for sale for US$3500 - The tube thing is supposedly a skull mount
The Orchid Island page also has a few artifact images.