This fossil gastropod specimen is a Sinistrofulgur sp. (related to the modern left-handed, Lightning Whelk).
It was were recovered from a Pliocene-Pleistocene deposit in the Bone Valley formation of south central Florida. This specimen has the characteristic blue coloration found in some Bone Valley pieces. This marbled coloration results from the unique mineral profile in the sediments and is considered highly-desirable by collectors (who sometimes refer to it as "Bone Valley Blue"). This piece has beautiful marbling of gold, blue, black, and white. This specimen is very large (approx. 9.5 inches long or 241mm) and is mostly complete with just the tip of the tail end and a few chips on the aperture edge. If not for these very-minor condition issues, this would be a "museum grade" specimen.
Note - I have provided photos of the specimen dry and wet. The coloration is brighter and deeper when the surface is wet. You could choose to coat this specimen with a sealer (Butvar, poly, varnish, etc) to give it that permanent "wet" look.
Refer to the photos. The black centimeter cube is shown for scale and is not included. The photos shown indoors on paper are DRY. The photos shown outdoors in the sunlight on a wooden plank background are WET. You are purchasing the specimen shown. Your purchase will include an ID label.
This specimen will be carefully packed for shipping to prevent breakage.