Named for the concentric rings on its shell, which look like the growth rings of a tree. A clam that records its age. The rings are raised ridges that encircle the shell, becoming more closely spaced toward the edge. Each ring represents a period of growth, a record of the clam's life in the sand. A shell that is a diary. It lives buried in the sand of sheltered bays and estuaries. The circular shape is an adaptation to burrowing. A round shell moves more easily through the sand than an elongated one. The clam twists its foot to rotate the shell, drilling down into the sediment. Within minutes, it can disappear completely, leaving only a small depression in the sand. Its small size and thin shell make it less popular for eating than larger clams, but its beautiful shell is prized by collectors. The shell is white or pale grey, sometimes tinged with pink or purple. The concentric rings are clearly visible, giving the shell a textured, almost sculptural quality. It is often found washed up on beaches after storms, where its perfect circular shape catches the eye of beachcombers. A complete ringed dosinia, with its rings intact and its colour still bright, is a treasure. The shell fits perfectly in the palm of the hand, a small, perfect circle from the sea. The ringed dosinia is not commercially harvested in New Zealand. It is too small to be worth the effort of a commercial fishery. But it is collected by recreational gatherers, who dig it from the sand in sheltered bays and harbours. The sheltered bay is calm. The ringed dosinia buries in the sand, circular shell, concentric rings. A beachcomber digs it up. The rings are counted. The clam was ten years old. It does not know it is a treasure. It does not know its rings tell time. It just wanted to filter water. A clam for the patient, for those who appreciate the small pleasures of the intertidal zone. The ringed dosinia is proof.