Helvetia, Arizona, located south of Tucson in the northern foothills of the Santa Rita Mountains, was a copper mining camp in the 1800s and early 1900s. When copper prices fell, the mines and smelter were closed. The Helvetia post office was closed in 1921, and the town was abandoned not long after. Helvetia is now a ghost town with only some inactive mines, a cemetery, and a few crumbling adobe walls remaining.
The adobe bricks, made mainly of sun-dried clay, are melting away, and soon it will be difficult to tell that a building once stood here.
Blue and green secondary copper minerals (azurite, malachite, etc.) are common in the mine dumps here, although most of them I found were just surface stains on the rock.