polished fibroid onyx pebble

semiprecious mineral gem stone jewel precious geodes pebble shingle beach boulder nodule oval rounded round rotund brushed faceted polished burnished bright shiny shining glossy cabochon onyx chalcedony quartz quartzose quartzous silica agate onyx arabic sardonyx marble calcite fibrous stringy filamentary fibroid fibrillar fibred band strip stripe streak lane bar striped tabby striated stripy streaky brindle aragonite carnelian brown cream beige ligh ecru green yellow gray white