agate quartz silica gem semi-translucent slice

achat agate aura background banded birthstone black brown chalcedony colored crystalline dioxide druse gem gemstone geode geology geomorphology igneous jewel jewelry light micro microcrystalline milky mineral mineralized multi natural nature orange pattern polished precious quartz quarz rock semi silica silicate silicon sio2 slice starstone stone texture translucent transparency transparent turbid volcanic white