Calcite in Brachiopod Fossils

Examples of calcite crystals forming inside brachiopod fossils.  In this case two different brachiopod fossils are shown.  The first image shows a Platystrophia ponderosa brachiopod from the Ordovician Period of Kentucky.  Two images following are of Orthospirifer brachiopod fossils from the Devonian Period of Indiana.

The rest are of Platystrophia ponderosa brachiopods.  The image make look slightly different in color, lighting and focus.  Two different Canon cameras were used to test close up abilities.  A Powershot Pro in Super Macro mode and an EOS DSLR with a 50mm macro lens.  Incandescent light was used and the DSLR white balance was not set right making the fossils look yellowish.