👉 Fissures are small cracks or crevices in a rock, soil, or other material. These can occur due to erosion, weathering, or geological processes such as tectonic movements, and they can be caused by changes in temperature, pressure, or chemical reactions within the material itself. Fissures are often seen on rocks that have been exposed for long periods of time, allowing light to pass through them but also exposing areas that may not receive much attention during their natural history.