coquina

noun

1. (countable)Any of several small marine clams, of the species Donax variabilis, common in United States coastal waters.

   “The pretty little coquinas (genus Donax, family Donacidae), often called butterfly shells or wedge shells, are distributed throughout the world. Perhaps the most noted species is the small Donax variabilis Say, so commonly found on the beaches of Florida. Coquinas live in droves just beneath the surface of the sand. Collecting coquinas is both a fascinating and tantalizing experience.”

   “They were filled with "coquinas," 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 coquinas, Sabbath had become God's beautiful gift to me and my growing family.”

2. (uncountable)A soft form of limestone made of fragments of shells, sometimes used as a building or road paving material.

   “The isthmus is nowhere more than about 8 or 9 feet above the water surface. The top soil is generally sand, with underlying coquina rock—a conglomerate of small broken shells held together by some natural cement.”