Please help Identify this rock

[Gold_Striker]

I am driving along 285 into the mountains. My very first trips to go metal detecting. I all of the sudden become aware of all the different rocks now. Please help me figure out what this is. pics taken on road side of a rock face with an unusual very black silty looking rock sandy even. At the bottom a pile of black sand. You can see small bigs of matrix aggregated together in veins and then some very small string veins of rust.

Well I am trying to learn what to look for that will tell me I am near gold.
http://s1206.photobucket.com/albums/...g?t=1288223667





and later on driving down pine valley road from 285 heading south in colorado



here is my album address I am going to add to it each time I go out so let me know guys if you see anything telling me I am near gold. If I find some I will remember you helped me and let you in with a share of the loot!

[Eu_citzen]

Probably Diabase, that black one. But could be several other things like metabasite.