set of various manganese ore stones cutout

background calcite collage collection crystal crystalline cut cutout epidote gem gemology gemstone geological geology isolated jewelry macro magenta manganese mangano manganoan manganocalcite mineral mineralogy natural ore out piedmontit piedmontite piemontit piemontite pink polished psilomelane raw rhodochrosite rock rolled rough sample semiprecious set stone tumbled tumbling unpolished various white