I've noticed the trend in posts about minerals, so I thought I'd add my thoughts to it. (waits for negative comments and 'move to graveyard' post)

Anyway, my thoughts are that we should be able to deposit minerals in the Lab, and the idea could be that they need it for repairs, or for looking after the battle sprites they have there. In exchange, the player could receive 1-5 crowns for each piece of mineral they deposit (RNG for the win!) and a pat on the back from Morlin.

If that takes no ones interest, I wont suggest new sprites, (too many posts on it already) but maybe we could use minerals to craft their respective shards, I.E: Breaking down Luminite will give you 4 Light Shards, Crimsonite will give you 4 Red Shards, Moonstone will give you Blue shards ETC..
I do understand a flaw with this idea, as I manage to gain 100 of every shard in a days worth of runs, but it's still a viable option for a use to the unused minerals.

As an addition to this, maybe instead of using it to make shards, you could have a new material, Light,Red,Dark,Blue,Green Chunks, and make them apart of particular crafting recipes, like shard bombs or tortodrone gear(*sigh*).

I hope you guys like my ideas.