Amethyst geode with white calcite crystals and stalactites

An amethyst geode from Santa Catarina, Brazil, with white calcite crystals and stalactites. Three mineralogical phases in one geode, visually discernible on the polished cut surface.

The main amethyst phase fills the volume with purple points. Stalactites document late growth phases with needle-shaped extrusions into the cavity. The white calcite crystals grew as a secondary solution phase on already formed quartz surfaces.

The Santa Catarina deposit provides the highest quality material for such multi-mineral constellations. Three-phase geodes are paleogeological documents: each mineral zone corresponds to a geochemical phase in geode growth over millions of years.

A museum-quality collector's item of architectural gallery dimensions, with documented three-phase genesis.