how to find installed gem is rmagick 2 or rmagick 1?

Dear Friends,

I need to install rmagick2.

when i give gem install rmagick, rmagick 2.13.1 is installed.

But how do i find whether its rmagick 1 or rmagick 2?

Is is the series starts with rmagick 2.... belongs to rmagick 2 & series
starts with rmagick 1.... belongs to rmagick 1?

Thanks in advance

Jose Martin