scoria stone, volcanic rock, black lava rough stones full of holes vesicles in dark color selling at mto wa mbu village, tanzania

abundant africa african alley arusha basalt black bubble business cavities color countryside dark east erupt full goods gray hole igneous lava magma many market mbu mto nature people pile pressurized pumice pumicite rock rough round rural sale scoria selling shop stack stone tanzania texture trade tradition traditional vesicles village volcanic volcano