On Jupiter Island lies the largest Anastasia Limestone formation in the state. This type of rock runs along the east coast of Florida from Saint John's County down to Palm Beach County. Anastasia formations are composed of embedded sand and coquina limestone. Coquina, meaning "shellfish" in Spanish, is a rock comprised of fragmented shells, mollusks, trilobita (a fossilized group of extinct arthropods (the bug-looking things)), and other invertebrates. Scientists date these rocks to be more than 2.6 million years old. 

The formation is located at the Blowing Rocks Preserve in Hobe Sound, at the southernmost point of the Indian River Lagoon. The 73-acre preserve is comprised of the ocean side, where the rocks are, and the lagoon side, which has an education center with exhibits and shady porch areas. The park was created in 1969 when residents of Jupiter Island generously donated the area to the Nature Conservancy. Besides the natural phenomenon and education center, there are also 3 hiking trails with boardwalks where you can view seabirds, plants and animals, like ospreys, beach sunflowers and fiddler crabs. 

When there are very high tides or during a storm, the ocean waves break upon the rocks shooting sprays up to 50 feet high. It is amazing to see and something comparable to natural wonders like Yosemite. During average tides, the beach is a great spot for swimming, snorkeling, and scuba diving because of how clear the water is and there are crevices to explore that are filled with reef fish. You may also see sea turtles in the water with you, as the area is a very popular spot particularly for the Loggerhead. During the summer, you can see nests, turtle tracks and even hatchlings if you're lucky. 

The preserve is open daily from 9 a.m. - 4:30 p.m. It is a $2 donation for the day. The park also does 40-minute guided walks every Sunday morning at 11 a.m. Blowing Rocks is located at 574 S. Beach Rd., Hobe Sound, FL 33455.