CiM - Obsidian. I thought this was another black - mostly because I was prejudiced by the name. However, CiM calls it a "very dark grey."
When I test a glass - I usually test it without any prior knowledge of what it might do. This allows me to discover new things about a glass. Or, sometimes to completely miss the point. (See the recent posts about CiM Cotton Candy and Effetre Earth. Oh well.)
Anyway - this glass looks black to begin with, and, as you can see in these two self-coloured spacers - they look black.