Sentence:  They were filled with "<WSD>coquinas</WSD>," tiny butterfly-shaped clam shells that gleamed with all the colors of the rainbow. Mario poured the sand and its brilliant treasure into my hands. I stared at the beauty and thought about God, Sabbath, and friends. A few weeks earlier this day had been an ugly thing to me, like the oily sand beneath my feet. Now, like the colorful <WSD>coquinas</WSD>, Sabbath had become God's beautiful gift to me and my growing family. 
Meaning of the word marked with <WSD> tags:  Any of several small marine clams, of the species (noshow=1), common in United States coastal waters. (from mid 19th c.)