Calcite flowers grown on black limestone sugared with small rock crystals

A specimen with calcite flowers on black limestone, the surface of which is additionally covered by a fine crystalline rock crystal crust. Three generations of minerals from the South Chinese karst caves of Guilin.

Calcite crystallizes trigonally in a variety of habits, here in the scalenohedral aggregate form known as flowers. The white to cream coloration comes from pure CaCO₃ without Mn/Fe trace elements.

The black limestone matrix underneath is sediment-organically colored bituminous material from the original cave floor. The thin rock crystal layer between the matrix and the calcite flowers testifies to a silica-rich solution phase that flushed through between the two carbonate generations.

Such three-layered calcite-rock crystal-limestone specimens are the hallmark of the Guilin region. Mining takes place underground in karstic cave systems.

A textbook example of hydrothermal mineralogy with a visual layer narrative.