Thank you for the answers. I know the olives look a bit odd, but it was a test render and have no intentions of fixing it for now. Probably ill try to make the olives make a little better later.
The main goal of this render was to test cycles’ render abilities and i am more then happy with the result! Cycles is fast, intuitive and very interactive! I encourage you to test it!
As for the dark parts of the olives - it was a happy coincidence. I have no idea how it happened, but it looks cool
Check the .blend file. I hope it will help you understand it better then i can explain
PS. sorry for my crappy english