I have tried installing Sass three times on Mac OS Sierra(10.12) from the terminal typing the following code:
sudo gem install sass
Then it
Buddy,
I just now faced the same problem exactly same.
$ brew install ruby
make sure homebrew is installed on your PC then I did
$ sudo gem install sass
The installation took place
$ sass -v Sass 3.5.1 (Bleeding Edge)
Hope it helps you too..