tumbled diopside gemstone on white

acantoide acimitediopside alalite background chromeaugite closeup coccolite collection cut cutout dark decorative dekalbite diopside diopsidic gem gemological gemstone geological green isolated kokkolith leucaugite macro malacolite malakolith mineral mineralogical natural object ornamental out pebble polished protheite pyroxene rock rolled sahlite sample specimen stone surface tashmarine texture tumbled white