", if it would be possible to just mine the diamond planet to nothing?"
No it wouldnt be possible. First problem you have is mining at all. To dig a hole into a planet sized Diamond is damn hard. Only thing humans could use are explosives. Next problem is transport and where are you going to store that diamond ? Also the main problem is the size . Humans have not nearly enough energy they could use to blast a planet into pieces and transport it somewhere. To mine a planet you would have to take material out of its gravitational influence or else the diamond would fall on its surface. It would take Billions of earths and the combined effort of every planets society and millenia to completly "mine" a planet away.
Also Diamond would be worthless it has no economic sense. Maybe people would start to use Diamond as a material to build houses and streets, bridges. (Not exclusively Diamond ofcourse, maybe with a concrete coating where people dont want to have a Diamond surface.) I still refer to Billions of earths if one earth could magically mine a planet away and take it home it would kill us all. And earth would stop existing.







