Hammerstones are smallish, fist-sized rocks that fit comfortably in a human hand and were used as hammers or other crushing tools. There will usually be damage on one or more sides of the stone: flaking, cracks, pits, or crushed areas.
These four stones were found on our property. I presume that a previous resident collected them from different areas in the Mojave desert and placed them throughout the property, afterwards forgetting about them, and leaving them behind.
Rocks rate high with desert rats. We search for them, collect them, save them, cherish them and even gift them. I imagine they were equally important to native peoples who may have selected these stones for their unusual beauty.