Proposal

Break Block should inherit enchantments of a tool in the same way Place Block can "pick" an item.
For example, casting Break Block with a Fortune 3 pickaxe in the slot immediately to the right of the casting item should inherit Fortune 3 for the block breaking spell.

But why?

There's no reasonable way to farm amethyst clusters efficiently in vanilla Minecraft. Amethyst is the main currency of Hex, so getting amethyst is important. The two main ways of getting more amethyst is to get Fortune 3, or Mind Flay a lot. Getting the ancient scroll for Mind Flay is currently completely dependent on how many structures you find.
If you get Fortune 3 on a pickaxe, you have to mine the crystals by hand, which seems like a good opportunity to encourage people to automate the problem.