Emmonsite, also known as durdenite, is an iron tellurite crystals. It is of a yellowish-green color, with a vitreous luster, and a hardness of 5 on the Moh scale.
Emmonsite was first described in 1885 for an occurrence in the Tombstone District , Arizona. It was named for the American geologist, Samuel Franklin Emmons, (1841–1911), of the United States Geological Survey
Emmonsite is found, often with quartz in the Tombstone It is also associated with native tellurium, pyrite, sonoraite