you must have gcc,json_pure
i collect some information from several post
sudo gem uninstall sass_x000D_
sudo gem uninstall compass_x000D_
sudo gem update --system_x000D_
gem install json_pure (if you have already have continued to next step)_x000D_
sudo yum install gcc gcc-c++ (if you have already have continued to next step)_x000D_
sudo gem install sass_x000D_
_x000D_
sudo gem install compass
_x000D_
Hi if ** sudo gem update --system ** not working you got an error in the update then use
sudo gem update --system 2.7.8