Medium in size "Duothunderball Egg" type of agate, two separate thunderballs fuzed together, one polished face, bands of chalcedony (brown, blue, white, translucent) other half of host rock, crystals beneath the dark black-ish colored area, some smoothed over crystal formations along edges and up top near blue, dull to vitreous luster, 7 on hardness scale Color: Black, Blue