What is the sand like on Florida's Gulf and Atlantic beaches?

Florida State Parks explains that the quartz comes from rock worn down on the continent and carried by rivers into the Atlantic and the Gulf, where currents and waves bring it onto the beaches. Tiny shell fragments make sand brown or light gray, coquina shell fragments make it orange, and black and brown fossil fragments make it dark gray to black. Along the southeast coast and in the Keys, the sand is often made more of coral and mollusk shell fragments than of quartz.

On the Gulf side, Gulf Islands National Seashore in the Panhandle has white-sand beaches, and the National Park Service says the sand there is always moving, by wind, currents or storms, usually from east to west. Park phone: 850-934-2600. At Delnor-Wiggins Pass State Park in Naples, the 1 mile of beach is almost pure white quartz. Park phone: 239-409-0637.

On the Atlantic side, at Canaveral National Seashore, sand grains and shell fragments have cemented into a rock called coquina. Park phone: 386-428-3384. The Florida Department of Environmental Protection's standard for sand used to rebuild beaches after storms allows slightly coarser and darker sand from Brevard to Miami-Dade counties than in the Panhandle, and on every coast it calls for predominantly quartz sand similar to the beach it goes on.

In the water, the National Weather Service warns that rip currents often form on calm, sunny days. It advises checking the local beach forecast, talking to the lifeguard, and swimming only at a beach with lifeguards. At Langdon Beach in Gulf Islands National Seashore, a lifeguard is assigned from Memorial Day to Labor Day.

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