Brochantite

Brochantite is a mineral composed of copper sulfate, recognizable by its acicular or prismatic crystals of a particularly intense emerald green to dark green. It forms in the oxidation zones of copper deposits, often in association with malachite, azurite, chrysocolla, or cuprite. The finest specimens, particularly from Morocco, Namibia, Chile, and the Democratic Republic of Congo, are highly sought after by collectors for their luster, vibrant color, and elegant crystalline aggregates.