Hello,

I'm making suggestions like you asked on forums.

The first idea is to use metadata for your various blocks, to save block ID. You could use an ID for each planet and metadata for different kind of blocks in each planet. (this will break all existing worlds, I know)

The second idea is to add unique items for each planet/moon which can be used for crafts (and tier evolution) or decoration. Some planets already have specific metals but not all of them so here are some examples:

• Mercury: Mercury Iron, since this planet supposedly has a huge iron core (in real). Mercury iron would be common on this planet (would replace classic iron generation), have a better durability than classic iron, and could be used for higher rocket tiers crafting (plates?).
• Venus: Venusian Sulfur, different from regular sulfur, hot material, could be used as fuel in furnace and in craft for higher tiers
• Ceres: Dolomite crystals (to use in crafts)
• Pluto: Black Plutonium, cf what Dream-Master said in issue #39

As for non-real planets (from other systems), we could create totally new materials (like the rainbow crystal). I don't have any idea for now...

Last thing, unknown and rainbow crystals have the same loot, you should make a new loot for rainbow crystal. And add ability to drop them with silk touch.