Why are minerals so cheap now?
The last time I played they were worth 5 crowns each, and I was contemplating saving them all until they went up in price a little bit. Now it's a few months later, I've got a couple thousand of them, and I find that they're only worth 2-3 crowns now.
What the hell? Is this a bad time to deposit them or something? When are they going to go back up in value?

The current status is that they have a base value of 3 crowns each. If the mineral type is in the two top for that Stratum, then it will decrease to 2 crowns. If the mineral type is dwarfed in comparison to other minerals in the Stratum, then it increases to 4 crowns.
Or perhaps vice-versa.
So I'm just better off saving my minerals again until they go up in value?

Don't bother. 3 is high now. The only time you'll see 5 again is if you dump the new gate right after another gate launches, I mean IMMEDIATELY AFTER. I think a four is possible if too many people try to force a gate before the shift, that's what happened to a fiend attempt on FSC one time.

mineral are used for changing the resulting gate them , not as a source of income. If i could choose i'd make minerals give 0 crowns when deposited.
Then I wouldn't ever bother collecting them.

I have been observing mineral prices multiple times per day for maybe four months straight. (Get a life, I know...) If you want to make money, save up minerals for when you see good prices. A good price for red, green, and yellow is 4 crowns per. A good price for blue and purple is 3 crowns per. (Occasionally I see blue and purple for 4, but it's really rare.)

So...We're all talking about 3cr income on minerals...
Is the CE market on the rise again? ;)

I didn't take advantage when I saw valestone was for 4 cr each..... ATM my large amounts of minerals help supply cr for lockdown fees.

...I mean even if it's so low that some players don't bother picking them up (I HATE YOU ALL) I can hoard them, cash them all out at one time and pretend I made a huge profit out of it... but that's not gonna happen since I'm in the business of gate conservation, fighting the people who are "fiending up" our clockworks.
...is this why we haven't seen a fiend-themed stratum in T2 lately?

Also, I try for a T3 with beasts in S5 and slimes in S6.
Come to think of it though, I have an excess of dark crystals right now. HEH HEH HEH.
My seraphic set, dark thorn blade and I would have no problem with seeing some fiend stratums pop up. (though I should probably get on with cooking up a skelly-series shield before I get too ahead of myself)
It would sure beat all the status themed stratums that we seem to have right now. I've been doing some equipment heating runs lately, and it's kinda rough having only one good sword on me when the monster type is completely random from floor to floor.
Youd be better off saving minerals to construct an easy stratum for yourself, then running it when it launches. I have like 50+ of each mineral saved up for when I need them. ><
I pick up the biggest minerals dropped per level regardless of color.
One day I decide a bit more CR to make a purchase.
I pick a random gate and autosell.
Gate creators the world over scream in agony and tear the hair from their heads.

up to just over 2k of each mineral type(a ton more purple then the rest) in a few years ill have enough to choose my own gate theme.
Maybe...you should have read the update posts by the devs? Like a few months ago?