semi-translucent slice of agate quartz silica gem

achat agate aura background banded beautiful birthstone black brown chalcedony dioxide druse gem gemstone geod geology geomorphology igneous jewel jewelry light macro microcrystalline milky mineral mineralized multicolored natural orange polished precious quartz quarz rock semitranslucent shining shiny silica silicate silicon sio2 slice starstone stone transparency transparent turbid volcanic yellow