Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Tahitian Moon Sand is absolutely BLACK. IT is fine pieces, too, so no sheen.
Pebble Tek quartz is a blend, and while the BLACK pieces are really black, it is blended with lighter pieces. The pieces are a bit larger, so you might get some reflection of the faces, too.
Soil Master Select Charcoal (not available any more) was quite dark, but not true black. Flat black (or charcoal). No sheen.
Eco Complete (at least, the bag I had) is BLACK. Pieces are irregular enough that there is not much, if any reflection.