Sphalerite is a zinc sulphide mineral with a chemical composition of (Zn,Fe)S. It is found in metamorphic, igneous, and sedimentary rocks in many parts of the world. Sphalerite is the most commonly encountered zinc mineral and the world's most important ore of zinc. Dozens of countries have mines that produce sphalerite. Recent top producers include Australia, Bolivia, Canada, China, India, Ireland, Kazakhstan, Mexico, Peru, and the United States. In the United States, sphalerite is produced in Alaska, Idaho, Missouri, and Tennessee. The name sphalerite is from the Greek word "sphaleros" which means deceiving or treacherous. This name is in response to the many different appearances of sphalerite and because it can be challenging to identify in hand specimens. Names for sphalerite used in the past or by miners include "zinc blende," "blackjack," "steel jack," and "rosin jack" - "".