Super dark amethyst geode from Uruguay with calcite crystal and beautiful agate rind

A very dark amethyst geode from Uruguay, with a striking calcite crystal on the inner wall and a distinct agate rind on the outer edge. Three phases of geode genesis are visible: agate base, amethyst wall, calcite late generation.

Agate rind and amethyst lining document the typical sequence of Brazilian-Uruguayan geodes: the oldest layers are the concentric agate bands at the edge, which form during early geode formation. Only then does the amethyst crystallize from the remaining cavity solutions.

The calcite crystal inside is the youngest generation: after the quartz phase was completed, calcium carbonate-bearing solutions penetrated the remaining residual cavity and allowed the calcite scalenohedron to grow. Three generations, one visible stratigraphy.

Uruguayan material from the Artigas Basin is among the premium deposits worldwide. Geodes with a complete three-layered genesis image are collector-relevant because they condense the geological narrative into one piece.

A collector's item with a three-stage mineralogical genesis.