A system (or an object, like the vell) could be put in place to put a barrier to the crystals to prevent them from breaking.
In case that giving each crystal its barrier is a problem, you could put a barrier system by crystal tabs. To recharge it like the vell/dekia, you need to break crystals to get materials. And that each death takes away a certain amount of durability of the barrier.
Example:
-If you die positive karma: you lose between 0-20 (0 to stage that you don't lose crystals) total durability points (example 100 total points).

-If you die negative karma between 20-40 points.
-If you lose all the durability that you can break the crystals normally (and this continue selling pearl items to recover crystals to those who have no memory ....)
To recharge the same as the dekia lantern can give a certain value to the crystals according to the degree and this maintain the market for crystals.
This would allow to go to more difficult game points without having so much fear of losing the progress of a week or more.
If you are wondering where to put an extra item in the inventory, if you move everything (including the riding crop) to the life tab, it would have a perfect place there.