Where to farm/buy upgrade mats?

[Kacho]

I need more powah but my material acquisition rate is SUB OPTIMAL. Where can I do the needful?

[slayer1065]

i believe you can buy the small and regular stones from the blacksmith lady aside from that i think bigger ones unlock when you give her more tablets one word of warning though even if you want to free the slave dont it locks you out of being able to buy chunks from her so give the 3rd tablet to her not him

[Ringo]

I farmed large shards from this guy before I had found any or any were available for purchase. Found it because I wanted the armor set. Drop rate isn't amazing but it's very quick once you get into the groove and how to kill him quick.

https://steamcommunity.com/sharedfiles/filedetails/?id=3051573527
https://steamcommunity.com/sharedfiles/filedetails/?id=3051573582
https://steamcommunity.com/sharedfiles/filedetails/?id=3051573495

[Tanktyr]

Medium size shard at Sanctuary shrine i think its called, those 3 mace guys, 1 just at the door exit and 2 outside, takes 20 seconds to kill and reset, And Large ones then the ruiner is the best one yeah, there is a few earlier but alot longer runs (2 big mace guys in The fens)
Can easily get your weapon to +5 at least before the boss with the dogs

[Kacho]

Appreciate the tips