And by chipping a few bits out, I wasn't suggesting you destroy this very interesting looking rock. Yes, having a thin section made would be certainly be definitive, but that's likely way beyond what would be necessary (plus, not usually of much value to the amateur collector without a microscope). I was more suggesting using a pin or needle to pry loose a few fragments from a discreet corner/side of the piece, and them examining those with a hand lens for any additional identifying features like # of cleavages, color of thin flakes or the powder (=streak), and any other features that might be observable.  But in lieu of that, the crystals do look pretty much like stilpnomelane.  It's a relatively common low-grade metamorphic mineral in iron-rich rocks.

But that "ironman" approach may not appeal to you if you like the sample the way it is, although it's also possible you might find some interesting features in seeing how the crystals appear different on a broken surface in contrast to how they look on the outer rounded surface. In any case, perhaps if you have a chisel you can chip a bit off with something like that (or a gentle tap with the pick end of a rock hammer, if you have one).

The suggestion to further break any chips you dislodge from the sample is simply to provide you with more surfaces to examine. If you break the grains into coarse sugar/salt crystal size (~1-2 mm or so), they should still be big enough for you to be able to examine them well with a 10X hand lens. But you don't have to further break them... if you see what you need to in the initial chunks, then you're set.  Just differentiating minerals with no cleavage from minerals with good cleavage should be pretty easy, because the latter ones will clearly appear to be sitting on nice flat surfaces; however, determining the number of cleavages and angles between them can be a bit more challenging.  You can practice your skills on salt from the kitchen... you should see three directions of cleavage, all at 90° to each other, forming little cubic and rectangular prisms. Use a needle to spin the grains around, and with your the aid of your hand lens, use the re-occurrence of light reflecting off the smooth planes as you rotate it to estimate to guesstimate the rotation angle(s).  And you might not even need to go to this much effort, since the two leading candidates at this point (hornblende and tourmaline) differ markedly in cleavage (2 for the former, none for the latter... you probably don't even need to bother trying to estimate the angle, although it's a good skill to develop in your ID toolkit).

The advantage to examining loose grains rather than trying to photograph (even photomicrograph) the broken surface really boils down to the fact that frankly, people photographing samples for ID purposes, as opposed to aesthetic purposes, tend to take really awful photos. It may be hard to ascertain the number and angular relationship of cleavage planes from a static photo (a video, where the sample is rotated around a single axis, would be more useful, but again, the ID videos we tend to get typically show a specimen being tumbled around ones' fingers, like they're about to roll dice in a craps game... lol.