What's the use of washing sand tables in the story of Stardew Valley?

Get a basin after completing the sacrificial mission. The first function of the pottery basin can be used to make a hat to wear on your head. The main function of elutriation pool is elutriation of ore. When you come to the river, the tool is selected to pan the basin. When there is luminescent substance in the water, it begins to elutriation ore. Get iron ore.

There is a white thing on the surface. Go to the neighborhood and click on the ore with this.