Sure. It is inherent in some rock chemistries to cleave along underlying crystal structures. This is Geo 100 level knowledge. If the underlying structure is cubic, the rocks will split with that tendency.

It's been shown mathematically that pentagonal structure is not possible. So if you found pentagonal splitting, I'd have to say it was unnatural. But cubic is trivial, even salt does that.

Google "What minerals have 90 degree cleavage"

I'll quote from a net search: "By-and-large, cleavages at 90 degrees to one another indicate a cubic form, cleavages at 120 and 60 degrees in the same sample indicate a rhombohedral form, and cleavages at acute to obtuse angles over long surfaces indicate a prismatic form".

Sure. It is inherent in some rock chemistries to cleave along underlying crystal structures. This is Geo 100 level knowledge. If the underlying structure is cubic, the rocks will split with that tendency.

It's been shown mathematically that pentagonal structure is not possible. So if you found pentagonal splitting, I'd have to say it was unnatural. But cubic is trivial, even salt does that.