Are Quartz Compositions portable to Linux? I am interested in using Quartz Composer to make some visualization programs, that I want to run on a Raspbery Pi. 
My question is, is it possible to run something made in Quartz on Linux?
No.  Quartz Compositions only run on Mac OS 10.4 and up.

There's a third-party tool, Qtzweb, which can translate a small subset of Quartz Composer patches into JavaScript WebGL code, which you could run in a browser on Linux.