This is the official Nexuiz icon designed by innovati (myself) a 2D artist on the Nexuiz development team.
It was designed in the GIMP during development because I had no suitable icon for Nexuiz on my KDE desktop at the time - this wasn't originally intended for full public release. It is designed in Everaldo's Crystal style (very close to my own) to ensure uniformity with the rest of my desktop at the time.
For some reason, this file was missing from the final release of Nexuiz - so I am making it available here for all Linux and Mac users. Windows users are stuck with the .ico that came with Nexuiz I'm afraid.
If you don't know already what Nexuiz is, it is a cross-platform open-source 3D Deathmatch game similar to Quake3, but with advanced graphic effects. http://www.nexuiz.com