revealing mine tile makes it softer?

[gravesmerch]

happened with Black Coal on a big cave wall, it was "very much too hard" all over the cave, but I found a spot a few tiles away, then went back and mined the whole wall and confirmed tile by tile, so maybe is not a bug, but maybe it is

[vatas]

Cave walls that have not been "revealed" could (technically) count as completely different tiles, since they don't yield anything, but do if they were revealed beforehand (barring the yield RNG or w/e determines exact amount of ore you get, which can be as low as zero.)

[lordgrunt]

In short, think of the grey cave walls as another type of vein. grey wall hardness is separate from what's hidden beneath. and grey walls will turn to actual stone when revealed by mining behind them, so you only dealt with hardness of coal all the time.

[gravesmerch]

interesting... so maybe stone types are defined on demand, instead of fixed a world generation... always wondered about that, but now i'm a bit more on the on-demand side