Black Lava is of volcanic origin, featuring a porous texture, making it very lightweight and versatile. Due to its comparably low weight, it is possible to create large structures with it.
For example it is possible to design a “Green Reef”. Green Reefs are tall scapes covered in various epiphytes like ferns of the genus Microsorum or Bolbitis, Pogostemon helferi or different kinds of moss. Their roots will find a good foothold due to the porouse sctructure of the stone. Individual stones can still be moved or exchanged later on, making the layout modular.
Also a classical Iwagumi can be made from Black Lava since the very dark colors make for a good contrast to the grey color of the more commonly used kinds of stone. As an advantage Black Lava does not increase the hardness of the tank water.
Lava rock is often used in conjunction with roots. The individual stones can be covered with moss to form forest-inspired scapes.