various unpolished black stones with names cutout

amphibole amphibolite background biotite black bornite chromite collage collection cut cutout description dunite flint gabbro garnet gray haematite hematite holystone hornblendeschiefer iron isolated knopite loadstone lodestone magnetite mica mineral name natural olivinite ore out peacock pumice pumicite raw rock rough sample schorl set specimen spinel stone tourmaline unpolished various white