Dgc1808 on 22 December 2009
Bladestone is probably the hardest because of the low drop rate and the fact that you have to kill black skeletons for a pure bladestone.
Most of the others, if you do a bit of exploration and always go for kills you should be able to get them all after a few playthroughs. [Assuming you're also changing WT with playthroughs.]
4 ≈ One
