【Pure Natural and Dark Color】Black lava is of volcanic origin and is rich in minerals and trace elements. It remains in its original state, except for being hand-picked and cleaned. It has a very dark color, a rough surface and a porous texture. Due to its comparably low weight, it is possible to create large structures with it. 【Diverse Types of Landscaping】Black Lava Rock is an essential aquascaping stone that's often used in all types of aquarium setups. It can be used alone or combined to create landscapes such as caves, cliffs, and mountains. In addition to direct use, it can also be crushed and used as a bottom, which facilitates the growth of plant roots. 【Suitable with Aquatic Plants and Ferns】Black lava is often paired with epiphytic aquatic plants and aquatic or terrestrial mosses. Simple aquatic plants find root footholds on stones easily and self-attach rather quickly. Moss-covered rocks can form a forest scene. 【Porous Structure for Bacteria Cultivation and Water Purification】The porous texture of lava rock creates a good habitat for the survival and development of beneficial bacteria such as nitrifying bacteria, making the aquarium environment healthier. The rough surface also has a filtering function that absorbs harmful bacteria, debris, feces and harmful heavy metal ions, keeping the water in the tank clean. 【Stable Nature and Activated Water】Lava stone is stable in nature, so it does not affect the composition of the aquarium and increase the hardness of the water, and it helps to stabilize the PH value and mineral content. It also promotes the activity of oxygen ions in the water, which helps the metabolism of plants and animals in the aquarium. LANDEN Black Lava Stone features its porous nature. It has a volcanic origin and is famous for its versatility. Black Lava Rock has also been known to make an excellent base for moss-covered stones as an accent to any aquascape. Its lightweight nature makes sure you get more volume per pound. Black Lava is always paired with branch woods, roots, and easy aquatic plants like Anubias, Bucephalandra, and fern plants. LANDEN Black Lava Stone is hand-selected and washed. It is inert and, as such, does not harden the water and has little to no effect. This set includes a variety of stones in shape and size we select cautiously one by one, which is perfect for a nature aquarium or Iwagumi style layout in planted aquarium.