I just can't get the green Sol's gem from the mines. I know where it is but I can't climb the pillars in the room with the z-pool. I 've read a walkthrough but it didn't help much. If anyone could give me a hint I 'd be gratefull...

I had the same problem for a while. Have you triggered the russian rocket launcher attack that blows up the track near the waterfall room? (past switch 3 on the outside track) Until that happens, a critical block will not shift to allow you to climb the pillars in the z room. If you have, then jump the water to the lowest block, climb the next 1 and then you can leave the room through a hole the attack made. A couple more jump/climbs will bring you back into the z room on top of a tall pillar. Jump to the other and 2 more jumps to the green gem.