You mean the stones like "Yellow limonite" and this? (sadly nothing I found yet, too :/)
And I'm not getting any rewards, since it's a "learn how to" I thought it's meant to be that way. (I think in 1.7.10 rewards are planned, if I read it right)
I found some mineral sands alongside water ... a few 'Basaltic' and a lot of 'Granitic'. They were mixed up with normal sand, gravel, coal and other stuff. I was actually only looking for gravel (for flint) at the time. Got smacked up by an enderman though, one life down. Swings and roundabouts!
Cool about no rewards - was just checking.