英文關鍵字
stones
rock
mining
metal
metallic
material
minerals
mineral
stone
rocks
element
iron
ore
shiny
mines
desert
industry
industrial
silver
tin
titanium
precious
metals
rare
chemistry
chemical
buried
sticking
piece
nugget
africa
african
brazil
china
america
russia
elements
export
product
raw
unfinished
unprocessed
australia
valuable