Sodalite is a rock of volcanic origin that can be used in aquariums as decoration. It is mainly used for its aesthetic appearance, as it has a beautiful dark blue color with white veins.

However, it is important to note that sodalite can alter the pH levels of aquarium water by increasing its alkalinity. This can be harmful to fish and plants that have specific pH needs. It is therefore important to regularly test the pH levels of the aquarium water if you are using sodalite as a decorative substrate.

It is also recommended to rinse the sodalite thoroughly before adding it to the aquarium to remove any dust or impurities. Sodalite can also be used to make aquarium decorations, rocky landscapes or hiding places for fish.