Amethyst geode with wide agate rim

A Uruguayan amethyst geode with a distinctly wide agate rim. The banding of the chalcedony prominently frames the violet inner crystallization.

The distinctly wide agate rim documents a long first mineralization phase with abundant chalcedony crystallization. Such wide agate rims are a deposit-specific variant in Uruguayan geodes.

Uruguayan amethyst crystallizes in volcanic geodes of the Arapey Basalt Formation. The deposits in Artigas and Salto have been the globally documented premium provenance for the darkest amethyst colorations for decades.

The polished cut surface shows the typical Uruguayan internal crystallography. Material of this size and coloration is manually selected for higher market classification.