Johnbaumite is a calcium arsenate hydroxide mineral.

It was first described in 1980, where it appeared in Franklin Township, Somerset County, New Jersey.

[4] Johnbaumite was discovered at Harstigen mine in Sweden in the 19th century, but it was described as svabite.

[5] It is named after geologist John Leach Baum (March 15, 1916 – October 16, 2011), who found the original specimen in 1944.

He was a significant contributor to the geology and mineralogy of the Franklin deposit, and the Curator Emeritus at the Franklin Mineral Museum.