Cotunnite is the natural mineral form of lead(II) chloride

Lead(II) chloride

Lead chloride is an inorganic compound which is a white solid under ambient conditions. It is poorly soluble in water. Lead chloride is one of the most important lead-based reagents...

 with formula PbCl₂.

It was first described in 1825 from an occurrence on Mount Vesuvius

Mount Vesuvius

Mount Vesuvius is a stratovolcano in the Gulf of Naples, Italy, about east of Naples and a short distance from the shore. It is the only volcano on the European mainland to have erupted within the last hundred years, although it is not currently erupting...

, Naples Province, Campania

Campania

Campania is a region in southern Italy. The region has a population of around 5.8 million people, making it the second-most-populous region of Italy; its total area of 13,590 km² makes it the most densely populated region in the country...

, Italy. It was named for Domenico Cotugno (Cotunnius) (1736–1822), Italian physician and Professor of Anatomy.

It was first recognized in volcanic fumarole

Fumarole

A fumarole is an opening in a planet's crust, often in the neighborhood of volcanoes, which emits steam and gases such as carbon dioxide, sulfur dioxide, hydrochloric acid, and hydrogen sulfide. The steam is created when superheated water turns to steam as its pressure drops when it emerges from...

 deposits. It occurs as a secondary alteration product in lead ore deposits. It has also been reported as an alteration of archaeological objects that contain lead.

It occurs in association with galena

Galena

Galena is the natural mineral form of lead sulfide. It is the most important lead ore mineral.Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms...

, cerussite

Cerussite

Cerussite is a mineral consisting of lead carbonate , and an important ore of lead. The name is from the Latin cerussa, white lead. Cerussa nativa was mentioned by Conrad Gessner in 1565, and in 1832 F. S. Beudant applied the name cruse to the mineral, whilst the present form, cerussite, is due to...

, anglesite

Anglesite

Anglesite is a lead sulfate mineral with the chemical formula PbSO4. It occurs as an oxidation product of primary lead sulfide ore, galena. Anglesite occurs as prismatic orthorhombic crystals and earthy masses, and is isomorphous with barite and celestine. It contains 74% of lead by mass and...

 and matlockite

Matlockite

Matlockite is a rare lead halide mineral, named after the town of Matlock in Derbyshire, England, where it was first discovered in a nearby mine...

 in the Caracoles

Caracoles

The Caracol people are an English-based creole speaking people who have been established in Northern Honduras since the early 19th century and are mainly of European British-Caribbean descent...

, Chile

Chile

Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...

. At the Tolbachik

Tolbachik

Tolbachik is a volcanic complex on the Kamchatka Peninsula in the far east of Russia. It consists of two volcanoes, Plosky Tolbachik and Ostry Tolbachik , which as the names suggest are respectively a flat-topped shield volcano and a peaked stratovolcano...

 volcano on the Kamchatka Peninsula

Kamchatka Peninsula

The Kamchatka Peninsula is a peninsula in the Russian Far East, with an area of . It lies between the Pacific Ocean to the east and the Sea of Okhotsk to the west...

, Russia it occurs with the rare to uncommon minerals tenorite

Tenorite

Tenorite is a copper oxide mineral with the simple formula CuO.-Occurrence:Tenorite occurs in the weathered or oxidized zone associated with deeper primary copper sulfide orebodies. Tenorite commonly occurs with chrysocolla and the copper carbonates, azurite and malachite. The dull grey-black color...

, ponomarevite, sofiite, burnsite, ilinskite, georgbokite, chloromenite, halite

Halite

Halite , commonly known as rock salt, is the mineral form of sodium chloride . Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, pink, red, orange, yellow or gray depending on the amount and type of impurities...

, sylvite

Sylvite

Sylvite is potassium chloride in natural mineral form. It forms crystals in the isometric system very similar to normal rock salt, halite . The two are, in fact, isomorphous. Sylvite is colorless to white with shades of yellow and red due to inclusions. It has a Mohs hardness of 2.5 and a specific...

 and native gold.