Aqua aura, together with other quartzes that have iridescence like angel aura, flame aura, opal aura and rainbow quartz are all artificially produced using high-tech processes to bond various metals onto plain quartz. Not something you would find at an abandoned mine in Tanzania.
It looks in the territory of ‘jelly opal’ to me. Opal has been mined in parts of Tanzania, but it would help to know exactly where this mine is, whether it has a name, and (if known) what was being mined there.