This is the name given to crystallizations of manganese oxides with black branching forms on rocks.
Although its beautiful and delicate silhouette reminds us of a fossil of vegetable or fern origin, pyrolusite is a mineral of the class of oxides and of the rutile group. Chemically it is manganese dioxide, which can present many forms of crystallization, although in general it is presented in this beautiful form of branches.
Their origin may be due to different processes; ours seem to have formed among the clays close to limestones existing in different parts of the municipality. The good ones are strange and those of Deleitosa are.