Well only because you are being denser than the pile of rocks. Obviously the comparsison is not of the materials they both are composed of. Duh?
Ok, I'll try this again, and I'll try to use smaller words so that you can understand.
Creationists like to draw a distinction between the created and the non-created by comparing a watch to desert sands. With me so far?
The inference that listeners (or readers) are supposed to draw from this analogy is that it is obvious from the appearance (or look) of the sands and the appearance (or look) of the watch, that the watch is created. Still following?
The problem with this analogy, from a creationist perspective, is that according to the creationist position, the sands were created as well.
Ok, now here's the tricky part for you...because, according to the creationist, the sands were also created, the analogy is fatally flawed in that there is no way to tell from appearance or look whether a thing, such as sands or a watch, is a created thing as opposed to a non-created thing.
Hope that cleared things up for you. Duh.