Sure if we could get there we could mine it (unless it has a dense CO2 Atmosphere like Venus or worse.) I was refering to mine the planet AWAY.
But sending the diamond masses from a star to the other would need so much energy it would be economically useless. Unless there would be a colony around the star anyway. And they would fire a couple of thousend H2 Bombs at once inside the planets crust to send some Surface chunks into orbit. Those chunks could be send onto a path directed to our solar system. Over the course of hundred of thousends of years the chunks eould reach the sun where our ancestors could take the diamond asteroids apart and let them fall onto earth. Maybe coat them with common Carbon so the Diamonds wont burn up. On earth they could be taken out of the sea and be used in the industry to make usable stuff. This scenario could make economical sense. But one thing remains. By the time this is realized we would be able to produce large quantitys of carbon nanotube material with even better properties then Diamond.
Mining in Space makes only sense in the solar system you are currently in. Mining Metall Asteroids between earth and jupiter is a good option one asteroid has more metall then was ever gound on earth and is easy to access compared to earth, once we have sufficient transport capabilities to near space. Diamond mining could only happen if we find a source around sun thats accessible.







