They call it the Emerald Coast for the blue-green water, but the color I remember best about the beaches of South Walton is white: wide expanses of sand so white it glistens in the sun. Few beaches in Florida or anywhere can match this 26-mile shoreline in Walton County, bordering the Gulf of Mexico in Florida's northwest Panhandle. The sand is nearly pure quartz crystal, dazzling to the eye and soft underfoot.