The porous stone formed after the volcanic eruption is very precious. When erupting, the magma that erupts has gas slag, solid magma. Temperature and pressure drop rapidly, chemical and physical changes take place, so the magma becomes volcanic. It contains a large amount of silicon, potassium, sodium, iron, magnesium, 26 kinds of mineral elements, as well as copper, zinc, chromium, nickel, manganese and so on. After heating, the volcanic rock will release a large number of misty energy ions, which will produce magnetic effect, thermothermal effect, cold and hot effect. Volcanic rocks are rich in trace elements, which are also produced by their accumulation. However, they are heavy and heavy, so after watering for a while, they will sink to the bottom...
3-6 mm#Granular Soil