Question: what is the most usefull material

Jarrod Hart answered on 12 Jun 2016:

It is a sad thing that the most useful material discovered by scientists is actually banned!

For much if the 20th century we had a material that could be molded to make roof and wall panels, it was fire-proof, strong and did not go brittle in the sun (like plastic). We could make fireproof paper or clothes with it, and it had excellent insulation properties (keeping in the warm and out the cold).
The best thing is it was cheap, it was a mineral you could find in most countries just sitting in the ground – so why is it banned?

Well you have probably heard of it, its called asbestos, and unfortunately, it causes cancer…

The mineral is made of thin strong fibres, which can be mixed with resin and molded into many things. Unfortunately, if the fibres get into your lungs, your body cannot get them out as they are sharp and dig in. Your body is also unable to dissolve the fibres so they stay in your lungs and corrupt the cells there, eventually, with enough fibres it is likely one of the cells with mutate into cancer.

So asbestos is my answer, even though, in the end, its completely useless!