PreviousNext RPC0126 - CALCITE in Mercenaria Permagna $1,050.00 Locality Rucks' Pit, near Fort Drum, Okeechobee County, Florida, USA Dimensions 198mm x 139mm x 137mm This is an exceptional specimen for the locality, containing two golden calcite-filled Mercenaria permagna clams in a dark gray micritic limestone matrix. The left-side clam in the first photo contains transparent yellow trigonal calcite crystals to over 3 cm in length, growing downward from the “hinge” area of the fossil. The right-side clam contains smaller yellow calcite crystals to 1 cm in length, filling the interior of the fossil. The shell sides of both clams have been naturally dissolved by slightly acidic ground water (the aqueous source of the calcium carbonate which has recrystallized within the clam), allowing one to see the internal mineralization. The specimen naturally sits well for display. The calcite is fluorescent blue-green under shortwave and longwave UV light (see second photo below), and even phosphoresces for a few seconds when the UV light is extinguished. These specimens are Plio–Pleistocene in age (1–2 million years old).