Geology of Coquina Rock

Coquina Rock was formed during the Pleistocene Ice Age, approximately from 1.8 million years ago, until approximately 11,550 years ago. The end of the Pleistocene Era corresponds with the retreat of the last continental glacier. Florida itself, and its landmass, was rising from the sea, and Coquina rock began forming along a long portion of Florida's East Coast, in the latter part of this era, and the global warming period that came with it. Marine life before the Ice age flourished in the seas, and again after the receding ice, marine abundance quickly recovered. Coquina Rock, and Florida became, as we know it today.

Coquina rock, geologically known as Donak Variabilis, is mainly composed of incompletely consolidated sedimentary rock. It is formed of billions of small clam-like seashell, called Coquina, or cockleshell. Overall composition of most Coquina rock is a mixture of these small marine clams, crushed oyster shell, mollusk shell, fragmented fossils, fragmented coral, crinoids, limestone, red sand, white sand, phosphate, calcite, and perhaps a little clay. It is relatively soft when quarried, and hardens over the years, after surface exposure.

Coquina rock, as it exists today, was formed along the East Coast of Florida. Formations can be found near the coast, from Palm Beach, Florida, then Northward to South of Jacksonville, Florida. Coquina rock can be found as far as 20 miles inland, and most deposits follow the Eastern Coast, and along the now I-95 corridor. Florida is not the only place it is found, as variations can extend into North Carolina. Coquina, and very similar formations of it, can also be found in many places around the world.

The Coquina rock sold at comes from the Northern end of Volusia County, and the Southern end of Flagler County. It is known as The Bulow Strain Series, or The Bulow Strain of Coquina rock. Many people believe the rock from here is the prettiest, because of the Orange color tint variations, and the extensive ocean wear, and sculptured look of the ones found here. So much so, that rocks from here are preferred, and can be found in uses all over Florida. The orange tint comes from the heavier mixture of this areas red sand. Coquina from other areas will vary in color, most of them lighter in color, due to their dominant mixture of lighter sand, and whiter sea shell, oyster shell, and limestone. Consistency and texture from our Bulow Strain Coquina can also vary, as the seas washed and moved different concentrations of each aggregate, in different quantity, and different depth, when forming.

You may have noticed that many Coquina rocks have "holes" or "half-moon" indentations in them, and ask how the hole got there, or if it was drilled into the rock. The answer is simple, that is where a palm tree, or even a large hardwood tree, grew at one time, as the rock was forming. When the tree and root base expired and decayed away, the hole remains.


What does Coquina mean?
Coquina (\kō-ˈkē-nə\) is Spanish for “cockle shell” or “tiny shell”.