UPDATE: The solution applies for Ubuntu 14.10, too (respectively, the problem arises in Ubuntu 14.10 as well).
If you install Skype on Linux Mint 16 x86_64 (KDE) you, you may find out the app won't start. And if you run Skype from the terminal to see what the error is and what the matter is, you may see the following:
skype: error while loading shared libraries: libGL.so.1: cannot open shared object file: No such file or directory
If you this error, here's how to fix it:
sudo ln -s /usr/lib/
x86_64- linux-gnu/ mesa/libGL. so.1 /usr/lib/libGL.so.1
This creates a link to the not found file / library.
Then on running Skype from the terminal, you may see another error:
skype: error while loading shared libraries: libGL.so.1: wrong ELF class: ELFCLASS64
sudo nano /etc/ld.so.conf.d/skype.conf
and add the following line in it
save & exit
and lastly run
sudo ldconfig -v
Now Skype should start up and run normally.