The logo banner on the Ruby home page has a nice reflective gem. I’m not
sure about the copyrights/trademarks for that particular banner on the
Ruby home page, and the Ruby Logo kit did not come with a reflective
version of the gem.
So I made my own imitation of the reflective gem using Gimp (with some
help[2]):
http://ruby-vpi.rubyforge.org/doc/images/ruby/
I hope somebody in the community can make a better reflective gem and
share it. Mine probably sucks. 
Cheers.
[1]http://rubyidentity.org/
[2]http://binnyva.blogspot.com/2006/12/creating-reflections-for-logos-in-gimp.html