This beautiful sample was recently collected from Pulaski County and donated because of the rare crystal shapes of the minerals. This cavity, or vug, was found in an igneous dike in the Jackfork Formation.

The photos below are magnified to show the crystal shapes. Notice the shape of the white calcite crystals that resemble poker chips. These crystals grew differently because of the cooling rate of the mineral-rich solution. Multiple growth stages are shown by the stacking of the layers. On top of the calcite are pyrite crystals that look like strips of wire, hence the name wire-pyrite or filiform pyrite. The pyrite crystals probably grew very fast to produce this shape. Enjoy the photos and If you have an ultraviolet light, check for fluorescence because this calcite also glows red.