Volkanix Aqua Fine Grade 10-20mm Lava Rock What is Volkanix Aqua Lava Rock? Lava rock is a form of igneous rock called Scoria that is created by the eruption of volcanoes. Scoria is formed when the molten lava solidifies, in that process air is trapped creating the porous, brownish red lava rock. The Volkanix Aqua range is produced specifically for the Aquatics market to ensure the best possible quality for your aquariums. Why use Volkanix Aqua Lava Rock? Volkanix Lava rock is PH Neutral it does not affect the hardness or softness of your water and will not degrade over time. This makes it perfect for aqua scaping and filtration media for your aquarium.