Non-crystalline material?
I'm not sure we're referring to the same thing. The "inclusions" have an amorphous appearance, as if they may have flowed or may have been smushed into hollows in the rock.
Examples below:
dark inclusions
They appear throughout the RATTed area of the rock.
Someone on Badastronomy.com suggested lava with vesicles, such as a'a rock. I suppose this is possible if the dark material flowed when melted then solidified.
Bob Clark