Black polished pebbles：

The main chemical components are silica, followed by a small amount of iron oxide and trace elements such as manganese, copper, aluminum and magnesium. They have different pigments, such as red red for iron, blue for copper, blue for copper, purple for manganese, yellow semitransparent as silica gel pulp, jadeite color containing green minerals and so on; because these pigments are dissolved into silica thermal liquid and different types, thus showing a thick, shallow and varied color, so that the cobblestones are black, white, yellow, red and dark green. And the green color.