Geo 730: Feb. 18, Day 414: Conchoidal Fracture

I suspect this fracture was created during the road-building process, but there's no way to be certain: it's an intrinsic quality of some rocks and minerals (not just minerals; basalt often shows conchoidal fracture too), so it's quite possible this is a natural joint. The scallop shape indicates that the fracture initiated from below, and propagated upwards.

Photo unmodified. August 19, 2011. FlashEarth Location.