Siesta Beach (sometimes known as Siesta Key Beach) is a beach located on Siesta Key in the U.S. state of Florida.
Unlike beaches elsewhere that are made up mostly of pulverized coral, Siesta Beach's sand is 99% quartz, most of which comes from the Appalachian Mountains.[1] Over time the feldspar and mica have been removed from the rock, leaving almost pure quartz. Even on the hottest days, the sand is so reflective that it feels cool underfoot. According to Harvard University geologists, it's estimated that the sand on Siesta Beach and Crescent Beach on Siesta Key is millions of years old, having its origin in the Appalachians and flowing down the rivers from the mountains until it eventually was deposited on the shores of Siesta Key.[2]
The southern portion of Siesta Beach is alternatively called Crescent Beach, which extends to the seawall and Point of Rocks, an area with coral and active marine life.
Siesta Beach is not only long, but also expansively wide, especially around the Siesta Key Beach Pavilion section. The beach is so wide the city installed walking mats to help beachgoers get to the shore, where they can then walk on firmer wet sand.[3]
Thanks to Harvard's geology department, which studies such things, you learn that the clean, flour-like sand is 99 percent pure quartz grains. Those grains are very fine, without coral or shell fragments.[dead link ]