Question Regarding Silver/Gold chests

[Mortal]

Those chests that needs silver/gold key to unlock and then you get a formula. Is there a way in-game to tell you that in the specific zone/region there are no more new formulas? I don't wanna waste keys.

Also, does different mining picks yelds better mining results? (That is my current assumption atm)

Thanks.

[gatsu86]

There is a book that will tell you which formula you missed and in which area, if I remember correctly that book is obtained from one of the Arena rewards.

EDIT:
I remembered it wrong, read hydr0xy1's comment below to find out how to find them.
ops... my bad, sorry. :)

[ShinkuTear]

Higher quality mining picks yields better mining results, to a degree.

When mining, you'll see that bar appear that drains with each swing? Better picks drain more of it. The later game mining nodes don't empty out quite as much per swing, but the picks and Karon skills to assist in mining matter more here, so you get a net positive as you go.

Using high end picks on early game nodes is overkill though :P

[hydr0xy1]

This is a little spoiler about formula but each region has 5 formulas. So if there are 5 equipment in mokyun's shop from formula, you've got all formula in that chapter.
The game will tell you which equipment comes from formula by icon of bent formula paper.