Just because it's sand doesn't mean it's all the same

Castle in the sand What do you think of when you hear the word "sand?" Do you picture a beach or a sandcastle? Maybe you think about throwing sand on an icy driveway up north. Is the sand you picture pink, black or white?

Depending on your experiences with sand, you might think it all looks and feels the same. But it doesn't.

Sand in Hawaii is black from pulverized lava rock. In Bermuda, it's pink from the weathering of coral reefs. Some beaches are called "cobble beaches" and aren't sandy at all, but rather are made up of pebbles and rocks (going barefoot on these beaches can hurt!).

Florida's coastline is 60 percent sand, and our sand varies in its origin and consistency. Just south of St. Augustine, coquina rock from tiny clam deposits makes up the shoreline. Sand in the Keys comes from weathered coral reefs. The shoreline along the Big Bend Gulf Coast north of Tampa and along the very tip of South Florida is made of clay rather than sand.

Much of the rest of Florida's sandy coastline is made of calcium carbonate and quartz. The calcium carbonate comes from marine plants and animal shells and skeletons that have been crushed into sand. (Here's something fun to try: If you add a bit of vinegar to this sand, the carbonates will make it disappear.) The quartz in this sand comes from mountains.

Most sand throughout the world is made of quartz rock. Wind, rain, frost and dissolved carbon dioxide reacting with rock mountains cause them to break down. Mechanical crushing from earthquakes, glaciers and rock slides further breaks up larger particles. Smaller pieces then move by wind, water or ice and travel to rivers or lakes to become sand dunes or beaches. Eventually they are swept into the oceans.

Over millions of years, the sand is buried and becomes sedimentary rock

Some sand is magnetic if it contains iron or magnetite. Usually this sand is brown or black.

Take a magnifying glass and look at some sand. The grains might be almost round, or they might be sharp and jagged. If they are rounded, they have probably traveled some distance, bumping against many harder objects that took off rough edges. If jagged, they probably haven't traveled far at all.

Sand particles vary in size and are classified from "very fine" (0.1 millimeters) to "very coarse" (2 millimeters). Anything larger is called gravel; anything a bit smaller is silt; clay is smaller still. Silt still feels gritty, while clay feels smooth.

But it isn't silt or clay that attracts most people to Florida. It is the beautiful sandy beaches. So why not visit one of our lovely Gulf Coast beaches? These natural wonders are just waiting for you to enjoy them.

Lee Belan g er is a seasonal volunteer trail

and canoe guide at Collier-Seminole State

Park. To contact her, e-mail Lungwort@

aol.com.

Take a hike or grab a paddle (and bring bug spray)

Although guided canoe tours and hikes have ended for the summer, there's much to discover on your own at Collier-Seminole State Park:

>>Rent a canoe - Paddle down the Blackwater River through a mangrove forest toward the Gulf of Mexico. Enjoy birding, fishing (salt water license required) or just a relaxing paddle in this outdoor wonderland. Rentals available from 8 a.m. to 3 p.m. daily.

>>Hike 11 miles of trails - Experience pine flatwoods, cypress areas and rare royal palm hammocks. One of three trails is interpretative, another allows for off-road biking, and a third has a remote campsite. Be sure to stop to register at the ranger station for the two longer trails and call ahead to reserve the campsite. Trails are open from 8 a.m. to 5 p.m. daily.

The park also offers picnicking, birding, fishing, camping, a boat ramp and a chance to see the historic "walking dredge" that was used to build the Tamiami Trail.

The entrance to Collier-Seminole State Park is at 20200 U.S. 41 East, eight miles east of Highway 951. Park entrance fee is $4 for up to eight people in a car; there is an additional fee for camping.

Call 392-3397 for more information.