dendritic opal. opal on a black background. opal is a hydrated amorphous form of silica. the mineral sample

amorphous artifact background black bohuskovice brown close collection colorful comes crystal czech dendritic detail europe form gem gemstone geology hyalite hydrated industry isolated kremze macro macrophotography mine mineral mineralogy mining mullers museum natural nature opal precious raw republic resource rock rough sample silica small specimen stone translucent transparent unprocessed water white yellow