This image is of a Montastrea sp. coral fossil on display at Mace Brown Museum of Natural History (August 2017). It dates to the Miocene Epoch (about 20 million years ago). The fossil was found in Miami, Florida USA.
The Mace Brown Museum of Natural History is located at the College of Charleston, 202 Calhoun Street, 2nd Floor, Charleston, South Carolina 29424.
Learn more at their blog: http://blogs.cofc.edu/macebrownmuseum/