Malachite at the Hall of Geology, Gems, and Minerals of the Smithsonian Museum of Natural History in Washington, D.C.

Malachite is made of copper, oxygen, and carbon molecules. It usually forms in blobular, fiber-like, or stalgmite shapes. But it can also form in large blocks (as seen here).

This sample is part of a large display given to the Smithsonian by the family of James Douglas. Douglas was a Canadian who left seminary to become a mining engineer. He became a director of the massive Phelps Dodge mining concern; purchased the properties that would later become the fabled Copper Queen mine near Bisbee, Arizona; and founded the town of Douglas, Arizona. He became one of the richest men in the world, and endowed a number of hospitals, libraries, universities, and other institutions in Canada.