I just found this outside and am wondering as to it's classification and minerals. Sorry if two pictures aren't nearly enough, thanks!

 

 

One of the first things a geologist does when faced with a sample, either a hand specimen like this, or a rock outcropping, is to hit it with a hammer to expose an unweathered surface. The problem wiht identifying your specimen is that it is thoroughly weathered - based on the degree of rounding it has spent time as a pebble in a river.

 

Now as to observations: generally brown; some small pock marks, possibly arranged in planar fashion; an irregular, lighter brown patch, free of such marks; couple of large 'holes'.

 

Not much to go on. Provisional guess - sedimentary clastic rock (clastic -composed of fragments or clasts). Poorly sorted (i.e. wide range of grain sizes). Conglomerate, or very coarse sandstone deposited in lower reaches of meandering river.

 

Where was it collected?