This bit of pen shell transformed to look just like one of the waves that broke it to pieces. Beautiful ocean tones catch the light in the pen shell’s shimmering, iridescent inner shell.
The science bits: A pen shell clam is a large thin-shelled clam. It is roughly triangular with an elongated pointed end. Inner surface iridescent with nacre, like that of an oyster. In life, these clams attach themselves to bottom sediment with byssal threads attached to the pointed end, like a mussel shell does. Some pen shells have thicker valves with heavy “sawtooth” ridges. Pieces that wash up are rarely whole, as despite their many layers, they are naturally brittle and break fairly easily.