Dendriet

Dendriet, in geological terms, refers to a natural, branch-like mineral pattern that appears on rock surfaces. These patterns are commonly called dendrites or manganese dendrites in English, and they are not fossils or plant remains. They are purely inorganic formations created by mineral precipitation that produces fern- or tree-like shapes on rocks such as limestone, sandstone, or shale, as well as on plaster or concrete surfaces.

Dendriet patterns form when mineral-rich water percolates through rock fractures or bedding planes. As the water evaporates or oxidizes, manganese and iron oxides precipitate and spread along the surface in diffusion-limited growth, creating intricate, branching forms. The result is a visually striking, feathery pattern that can resemble vegetation, but it is the product of mineral deposition rather than organic growth.

In appearance, dendriet patterns vary from delicate, lace-like lines to more robust, sweeping branches. Colors are typically black, dark brown, or gray, though lighter or mixed hues can occur depending on the minerals involved. They are often found on exposed rock faces, quarry walls, or within cave walls where mineral-laden solutions have traveled along surfaces.

Dendriet patterns are useful in geology and paleogeography mainly as indicators of historical fluid flow through rocks and surface alteration. They are benign curiosities for collectors and are frequently mistaken for fossil leaves or ferns, but they have no biological origin.