Exactly what it says on the tin. When splitting rock/celestial crystals I constantly pick up the crystals before they split. Making it impossible to pick up the crystals while holding the cutting tool would solve this problem.

If I'm understanding the tome's flavor text on the cutting tool where it talks about timing, this "mini-game" of avoid-picking-up-the-item is an intended function. What I've found that works best for me is to take a quick step back after throwing the crystal so it's still within tool use reach without being in auto-pickup range.

To make the items easier to actually hit (since a normal item's hitbox is much smaller than its model) i've increased the size of the hitbox, inadvertently also making it easier to be picked up unfortunately.

I'm not sure a "unable to be picked up" is a good solution either as the next issue report regarding this would be that it cannot be picked up when a cutting tool is held...

As a possible solution to this issue, why not make a pedestal or a cutting table to hold it in place? It would seem to be the logical answer to the "pickup" problem. Then, you could make the process of cutting the gems into an actual "mini-game" of sorts and possibly expand on crystals stats.

As I understand it now, the stats on the crystals don't really give any really meaningful improvement to the crystal as they only give a small percentage boost per level. I could be mistaken, so take that criticism with a grain of salt, I am unsure of the actual percentage improvements.