To be honest it's starting to become 3 iron = 1 grass unfortunately. 1 diamond usually equals to 64 iron (what I sold today actually) And usually 1 diamond is 20 grass, maybe 21. So 1 diamond is equal to diamond obviously so... 64 iron = 20 grass So that means that 1 grass can get you 3.2 iron. This is quite rough (4/20 =1/5) so these prices may vary. So unfortunately the price of iron is dropping because of /kits for iron and donor packages.