^It's definitely possible, like I said, charcoal was my first thought, and you can't tell for sure from the photo. I have doubts about charcoal it because as you say, charcoal tends to be dustier than that, plus, the effect on the bottle would be achieved easily by using the side of the pastel, and the richness of the black makes me suspect pastels as well. Of course, all those could be effects of the photograph. As for using a super light brushing of charcoal, that won't change the color of the charcoal, just the density. The grey on the checked handkerchief is laid on thick, and you can see the pencil strokes -- that could be a grey pastel or a soft and light pencil.