basaltic lava ejected as fragments from a volcano, typically with a frothy texture
火山喷出的(尤指泡沫质地的)玄武岩火山石碎块。
slag separated from molten metal during smelting
(熔炼时从熔化了的金属中分离出来的)矿渣。
"late Middle English (denoting slag from molten metal):via Latin from Greek