Everyone who has seen the short-lived coinage of Katanga has seen on the coins an image looking like:

The image shows a real Katanga Cross - the weight is just short of 1kg and the diameter is ~25cm.
They were produced for centuries in Katanga and the northern Rhodesia region (ie today's Zambia and Zimbabwe).
The exchange value of these crosses (which are considered primitive money) was roughly:
- ten kilos of flour
- five/six fowls
- two length of good cloth
- three/four kilos of rubber or
- six axes
Two of those would buy a gun.