Types of Rocks Found in Turks and Caicos Islands: A Guide to the 4 Most Common You Will See

The land masses that make up Turks and Caicos Islands were formed from limestone made up of the skeletal remains of marine life over time. 

The interaction of the warm salt water, the shell generating marine life and natural erosion have created beautiful caves and other rock formations. 

Types of Rocks Found in Turks and Caicos Islands


The information provided in this article by YesDirt.com is for informational purposes and is subject to change. Laws are updated. Accessibility guidelines and restrictions change. Be sure to confirm the land status and collection rules before you travel to an unfamiliar location or collect any material.

Oolite Rock

Oolite rock is a collection of marine shells and fossils cemented together.

Oolite rock is a denser, small particle type of Oolite. 

Oolite rock is formed from ooids.

Ooids are small rounded collections of calcium deposited around a grain of sand or other particle. 

These small bead like formations can become compacted together resulting in Oolite.  

While ooids are generally whitish in color they may appear gray or even pinkish in the presence of iron. 

Some ooids are microscopic and can only be seen under magnification. 

Oolite can be found in many places around the world, but geologists are not sure how it came to be so prevalent in the Bahamian Island Chain.

While there is an abundance of calcium containing shells and organisms to form the ooid, the water conditions are no longer favorable for their formation. 

The conditions must have been much different during the time they were deposited on the islands. 


As water erodes limestone it can form gypsum deposits when it evaporates.

This is most evident in the many caves on Turks and Caicos. 

Middle Caios has the largest cave system in the Bahamian island chain and inside you can see the evaporated limestone forming gypsum deposits. 

Gypsum is a very light colored rock made up of calcium sulfate dihydrate.

It is the main component in drywall, plaster and classroom chalk. 

These white rocks have many of the properties of drywall, they are light in color and crumble easily when you handle them. 

Gypsum can also form transparent crystals called selenite.

Selenite may be found in caves and it is often soft enough to bend in your hand. 

Selenite is named after the ancient Greek word for Moon and does not contain significant amounts of selenium. 

Fossilized Reef 

The living coral reef that is present in the waters surrounding Turks and Caicos has been there for many many years. 

When coral dies it can be fossilized in the limestone mud at the bottom of the ocean. 

Coral fossils are generally light in color and very porous.

It can easily be mistaken for a type of shell as it often form regular ridges or waves similar to many common sea shells. 

Coral fossils may be light for their size and may be very large or part of the sand particles on the beautiful beaches of Turks and Caicos.  

Fossiliferous Limestone

Fossiliferous limestone is limestone that contains many fossils.

Limestone can form rather quickly and it can encase plants or animals creating fossils. 

Fossiliferous limestone may look white to dark grey and the fossil or fossils may not immediately be visible.

Fossiliferous limestone may look very regular, being made up of many very small fossils, or very irregular containing large shells or shell fragments. 

Look for color differentiations in the limestone.

Most fossils have a slightly different color than the surrounding limestone. 

Some fossils are made up of very small animal remains like those found in plankton, to see these fossils you may have to use magnification.

It may not be immediately obvious that you are holding a fossil.  

Many examples of fossiliferous limestone look like sponges with many irregular holes and a porous texture. 

There are many types of fossiliferous limestone, so be sure to carefully examine any interesting limestone formations you see. 

Visiting Turtle Rock

Turtle rock is a popular destination on Turks and Caicos.

The island is a large limestone rock that is split in half by the erosion from ocean water and karst. 

Karst is the action of wind and water eroding limestone to create various fromations like towers, caves, cliffs, sinkholes or other formations of limestone.

Karst created the landscape of almost all the islands in the Bahamanian Island Chain.

Turtle rock is a small island that was formed by karst and it gives a clear picture of how the process happened on larger islands. 

You will notive that Turtle Rock supports very little vegetation as limestone generally cannot support fertile soil.

You will also notice the lack of fresh water.

Sink holes formed by karst may collect small puddles of freshwater. 

Larger sinkholes that hold rain water are called blue holes.

The freshwater floats on top of the salt water and can be harvested for drinking. 

Inhabitants once relied on these blue holes for fresh water, but now Turks and Caicos residents collect rainwater in cisterns to support their freshwater needs.

Over 90% of the island uses imported bottled water for drinking. 

Collecting Rocks in Turks and Caicos Islands

As a general rule, do not take any samples or remove any natural material from Turks and Caicos Islands without first asking a tour guide, employee or other official. 

The goal is to respect the preservation of these formations so they can continue to be enjoyed and studied. 

Many of the most popular beaches on Turks and Caicos are part of protected national parks. 

Grand Turk, the capital of the Turk Islands is part of the Columbus Landfall National Park.

While Princess Alexandra National Park protects many of the other most popular beaches. 

Protected beaches include:

  • Governor’s Beach
  • Cruise Center Beach (SunRay)
  • Grace Bay Beach
  • Leeward Beach
  • Bright Beach
  • Smith’s Reef
  • English Port 
  • Pillory Beach

Collecting shells, stones, sand or other natural objects in these national parks is prohibited to prevent the destruction of habitat and mitigate the threat of invasive species. 

Be sure to read and obey any posted rules or guidelines as you interact with the natural beauty of the islands. 

Types of Rocks on Turks and Caicos Islands

The limestone that formed the islands in the Caribbean tells us quite a lot about the history and formation of the island. 

The years of marine life, the shells, skeletons, exoskeletons and algie all compressed together to form limestone. 

Finding a fossil or an Oolite is an exciting piece of that geological history. 

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Types of Rocks Found in Turks and Caicos Islands