I could look in my old blasting manuals, but I doubt I would find any specific numbers on brisance, etc. As a blasting agent, black powder formulations have almost disappeared. Perhaps have by now. Going from memory, black powder deflagrates at around 1200 fps (which can vary greatly depending on things like containment, pressure, prill size, etc), while B-line, which many here would know as det cord), in comparison burns/detonates at 22,000 fps.
I only had one blasting job involving black powder way back when I briefly followed my dad and grandfathers into the mines, and that was at a quarry working under another ticketed blaster familiar with black powder. Black powder is used in some applications other than the normal forcite/xactex/ANFO formulas because it gives the rock more of a thump, rather than a smack.
In most mining, either underground or open pit, the idea is to shatter what you're blasting as much and as finely as possible. In quarrying granite, marble, etc, the idea is to break the rock absolutely no more than necessary to make it just small enough for machinery to handle it and get the chunks to the machinery that turns it into counter tops, tiles, headstones, etc.
There are a couple of businesses here that have racks of marble/granite slabs stood outside for display as though they were new cars sitting on a dealership's lot. Looking at the price tags on each of those raw slabs, they might as well be new cars for sale - and that's before they're ultimately cut to the finished size for whatever their purpose will be.