The main chemical composition of 4-6mm stone rice is silica, followed by a small amount of iron oxide and trace elements and compounds, such as manganese, copper, aluminum and magnesium. They have different pigments. For example, red is iron, blue is copper, purple is manganese, yellow is translucent silica colloidal chalcedony, the color of emerald contains green minerals, etc. Because these pigment ions are dissolved in titanium dioxide, the type and content of silicon hydrothermal solution are different, so there are various shadows and shadows, making the pebbles appear black, white, yellow, red, dark green, blue and gray.