3.3" Agatized Coral Fossil Oligocene and Miocene Epochs Tampa Bay Florida
Location: Tampa Bay, Florida, United States
Weight: 3.7 Ounces
Dimensions: 3.3 Inches Long, 3.1 Inches Wide, 1.2 Inches Thick
The item pictured is the one you will receive.
Oligocene and Miocene epochs, 34 million to 5.5 million years old
Agatized Coral from the Tampa Bay region is a fossilized form of coral in which the original calcium carbonate skeleton has been replaced by silica, primarily in the form of chalcedony, a microcrystalline variety of quartz. This transformation occurs through a geological process called permineralization or replacement, taking place over millions of years. During this process, silica gradually infiltrates the porous coral structure, preserving even the finest details of the ancient organism, including its septa and corallites. The resulting agatized coral combines the intricate beauty of the original coral with the hardness and durability of quartz, making it highly valued for lapidary work and gemstone purposes.
The formation of agatized coral in Tampa Bay is linked to specific geological conditions. During the Oligocene and Miocene epochs, Florida was submerged under shallow marine waters, supporting extensive coral reefs. Subsequent changes in sea level and geological uplift exposed these ancient reefs to terrestrial environments. Groundwater rich in dissolved silica then percolated through the coral, leading to the gradual replacement of the organic material. The presence of iron oxides and other trace minerals within the silica can impart a variety of colors to the agatized coral, including white, gray, brown, red, and black.
The distinctive banding and concentric formations characteristic of agatized coral emerge from variable silica deposition patterns or the preservation of ancestral growth structures within the original organism. Technically classified as a pseudomorph, this specimen represents a complete mineral replacement wherein chalcedony has assumed the coral's original morphology. The Tampa Bay region stands as a premier source for such specimens, with this 3.3" example likely extracted from fossiliferous limestone strata or alluvial deposits endemic to the area. These formations exemplify the geological artistry of the Oligocene and Miocene epochs.
