My cooling fan has enough power to suck pieces of loose plastic up
um, it should be BLOWING.
Usually the fan label goes on the inside - check that.

Have you tried printing the graphite at a higher temperature ?
The current trend seems to have People printing pla at a very low temp.

Even the same brand of pla will print at different temps for different colours.
Filament actually looks goldish and definitely looks like under extrusion. What temp
and speed are you printing at ?