PDLA-G-01 Origin: China Grade: A Dimensions: Approximately 30-40mm Weight: Between 15 and 25g Origin: China Grade: A = good Chinese lava stone pebble approximately 30-40mm Shapes, patterns, and colors may vary from one stone to another. Of volcanic origin, lava stone results from the cooling of molten magma ejected during volcanic eruptions. The magma is at a temperature of 1000°C and is then suddenly exposed to the outside temperature. When the volcano's lava comes into contact with the atmosphere, it cools and creates the famous lava stones. Lava stones are actually flows of cooled magma.