/usr/share/gwyddion/glmaterials/Obsidian is in gwyddion-common 2.50-2.
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
0.05375 0.05 0.06625 1.0
0.18275 0.17 0.22525 1.0
0.332741 0.328634 0.346435 1.0
0.0 0.0 0.0 1.0
0.3
|