Anyone know the point of them? I have about 20 thinking I would need them. 100 hours later a I still havent used them?

Wondering this too. I'm guessing you can build them into complete gems somewhere.

If you cant, you can bet on someone making a mod to let you smith soul gems with the fragments.

They're purely aesthetic/roleplaying items, like plates, baskets, etc.

Someone obviously tried to free a captured soul...

makes sense, considering all the ones i have found look like broken black soul gems, haven't ran across any regular broken ones yet