Well, it should be obvious that these are radioactive. You don't want to be here without the relevant protective filters on your suit. Ordinary radiation protection will not do. You'll need superior protection, such as Mutavisk Armor. Plants manage to grow here, and life manages to flourish. So it can't be ALL bad, right? These planets tend to be quite rich in Uranium and are the only place you can find Irradium.
Codex description Edit
These radioactive rocks are curiously abundant in native life. Granted, it's not edible and you still don't want to hang out there too much. You'll find heaps of radioactive resources here, obviously.
Possible Weather Edit
Anti-Gravity Rain, Light Anti-Gravity Rain, Algae Rain, Fog, Acid Rain, Small Meteorites.