He said conduction... as in heat transferred between to attached bodies...

A black object will loose heat by radiation quicker then a silver (reflective body) but it will also heat up faster as it will "soak" up the radiation. As it's not a perfect black body it will retain more heat then it looses through radiation so I'd go with silver if you want to reduce heat gain.
So tin foil and an insulator like a ceramic would be ideal (apart from the weight and possible fragility of the object)... other wise I'd say
black looks cool but steve1981 is right