Yes, baryte can certainly have very distinct colour zoning and internal fractures like this. In fact, many of these larger Sardinian crystals show exactly this effect. I have a few in my collection that show exactly the same effect. I also think it's one continuous crystal structure rather than an aggregate in which multiple crystals grew together, although that's a little difficult to judge from only these photos.
The 90° angle is visible in your second photo, as you rightly point out. This shows the crystal system is orthorhombic, whereas calcite would not have this right angle as it's trigonal.