I am starting to have a good amount of purple crystals, however the more I collect the better.
After the events in the mine, I have taken a good look at myself; several shards can be found on my body. Although I do feel them, they do not pain me -however, I still am unaware of the side-effects.
The explosion released healing energy from the crystal, I suspect them to be similar to the spells, and thus I will require some information on them. With this, I might be able to determine an important factor in their growth.
Sergeant Marshall also came with a slightly more fantastic theory on their growth; a counterbalance the evil present in the Underdark.
I do believe that if I can dissolve many small crystals, I can make bigger ones with time; to hasten the process, I would however need to turn them into powder, and find a suitable solvent, if water is not.
I've also in my possession a large crystal, the biggest seen that I know. I intend it to be the root of growth of other crystals... if I can find a place.