After learning about PSRJ1719 - 1438B, an entirely Diamond Planet, I feel that Starbound should bring back Crystal Planets or Diamond Planets and implement them more deeply than they used to be. I know we have Geode Biomes, but entirely Crystal or Diamond Planets would be fun. Maybe make them like a 0.1% chance to form around fiery stars. Since they're so rare, you wouldn't need to redo the entire universe in order to implement them. You'd be able to just add them in randomly once in a while and keep the current coordinates intact.
Yes. And all of the crystal-related mini-biomes should have a chance to spawn on the planet, too! And the monsters that spawn there should all be crystal themed, generated via a unique creature creator.
