Version: 26.3.461

Note that this might be intentional behavior, but I'll still report it just in case.

A Plasma Cutter breaks Quantanium quickly (although not instantly), but it drops nothing. You can still collect Quantanium with a Pickaxe.

If Quantanium not dropping when broken with a Plasma Cutter is intentional, perhaps the mining speed should be lowered to avoid destroying it unintentionally.