A Curious Texture

I walked down to where the packed dirt path meets the rocky shore. Among the ordinary gray pebbles, a small piece of dark slate caught my eye. It was nearly a perfect triangle, completely smooth around the edges from the tides. I crouched down and turned it over in my palm. The underside was cool and had faint ridges like tiny fossilized ribs. I cleaned off the damp sand with the cuff of my sleeve and placed it safely into my cargo pocket. It fits just right.