Box of Souls marbleizing, Stage 1

Having officially completed the Treasure Chest for my Pirate nephew, I am now turning my attention to Death's Box of Souls* to accessorize my other nephew's costume.

So far the Box of Souls has just received a layer of heavily pigmented black paint and a coat of gloss acrylic sealer. At that point it looked good enough to leave as-is, and I imagine that for future projects I will do something that is simply high-gloss black. But the plan was to apply a faux marble finish to this, and I am determined to follow through. Here's stage 1 of the marbleizing.
I am not 100% happy with this outcome: the paint was much thicker than I expected, and the gray dominates a lot more than I had hoped. Plus I committed the cardinal sin of overworking the piece, something I tried to compensate for by overdaubing with black. The whole thing will need to dry a day or so before I give it another coat of gloss acrylic sealer and then apply veining (and possibly additional black daubing.) After that I will spray on a final coat of acrylic sealer and then finally brush on a topcoat of high-gloss varnish, resulting in a total paint thickness of about 1/4". Hopefully the end result will not be complete crap. Stay tuned...

*So what in Hell's name is Death's Box of Souls? I have no idea. I'm just making it up, because I can't give a hand-finished box to one nephew and not the other. But as best I figure, Death (in Milton's sense of Death as a weird embodied side-effect of the fall of the rebellious angels) keeps his own private tally of the deeds of every soul, perhaps in, say, a big hourglass full of gems. Each gem represents a deed: white for goodness, black for evil, red for courage, green for generosity, yellow for cowardice, clear for purity of action, blue for...whatever. At the end of a person's allotted days the hourglass is shattered and the accumulated gems are poured off into a box, which Death carries with him when he goes to claim the soul. For souls that make it into Heaven, all of the gems turn to clear when the soul is admitted. But for souls that go elsewhere, the gems are tallied to determine the nature of the soul's fate. Hey, that sort of sounds consistent with Dante's Inferno too, doesn't it?