The surfaces of limestones are often marked by black or red-brown deposits known as mineral dendrites. These are deposits of hydrous iron or manganese oxides formed when supersaturated solutions of iron or manganese penetrate the limestone and are precipitated on exposure to air at the surface. Mineral dendrites have a fractal appearance, but the origin and characteristics of this morphology,
The term "dendrite" comes from the Greek word dendron, which means "tree".
|Manganese dendrites on a limestone bedding plane from Solnhofen, Germany.|
In paleontology, dendritic mineral crystal forms are often mistaken for fossils. These pseudofossils form as naturally occurring fissures in the rock are filled by percolating mineral solutions. They form when water rich in manganese and iron flows along fractures and bedding planes between layers of limestone and other rock types, depositing dendritic crystals as the solution flows through