/usr/share/gwyddion/glmaterials/Ruby is in gwyddion-common 2.44-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 | Gwyddion resource GwyGLMaterial
0.1745 0.01175 0.01175 1.0
0.61424 0.04136 0.04136 1.0
0.727811 0.626959 0.626959 1.0
0.0 0.0 0.0 1.0
0.6
|