Difference between installing gems and igems? ERROR: http://rubygems.org/ does not appear to be a re

Ruby IronRuby
1

I’m working on Ruby and IronRuby to use with Cucumber. What is the
difference between installing gems and igems?

When I; for example; “gem install -rspec”, it works good.

But when I “igem install -rspec”, it always gives an Error:

ERROR: http://rubygems.org/ does not appear to be a repository

ERROR: could not find a valid gem ‘rspec’ (>= 0) in any repository

is there any way I could install igems?