Pebbles are mainly composed of silicon dioxide, followed by a small amount of iron oxide and trace elements, as well as compounds such as manganese, copper, aluminum and magnesium. The reason for its formation is that the broken rocks, after long-distance transportation, make the corners disappear and form round or oval stones, which are produced in rivers, lakes and seas all over the country. Most of them are round and tangible, and the stone patterns are banded, striped, variegated, corrugated and irregularly curved, mainly in black, yellow and cyan. The surface is delicate, smooth and flat, and the stone is solid. Most of them are irregular blocks made of wax or glass