One of the world's finest mineral specimens, the Newmont Azurite was discovered in 1952 and used by a miner to pay his bar tab. The Newmont Azurite is known for the large size and perfection of its crystals. Dark crystals stand on tan calcite, perfectly formed and unblemished.
The Newmont Azurite was formed by the interaction of rainwater and groundwater on primary copper ores. It appears black, but the right light shows it to be dark blue. Despite azurite's beauty, it is too soft and too fragile to be used as a gem.
Harry Frank Guggenheim Hall of Minerals