Find a lot of posts on it and followed what they say but does not work for me.
What i did
brew install imagemagick gem install rmagick
it shows me following error
checking for Ruby version >= 1.8.5... yes
checking for /usr/local/bin/gcc-4.2... yes
checking for Magick-config... yes
checking for ImageMagick version >= 6.3.5... yes
checking for HDRI disabled version of ImageMagick... yes
checking for stdint.h... yes
checking for sys/types.h... yes
checking for wand/MagickWand.h... yes
checking for InitializeMagick() in -lMagickCore... no
checking for InitializeMagick() in -lMagick... no
Can't install RMagick 2.12.0. Can't find the ImageMagick library or one of the dependent libraries. Check the mkmf.log file for more detailed information.
Thanks
Here you'll find the answer. I had the same issue and this solved perfectly!