Phosgenite is a rare mineral consisting of lead chlorocarbonate, (PbCl)₂CO₃. The tetragonal crystals are

prismatic An optical prism is a transparent optical element with flat, polished surfaces that are designed to refract light. At least one surface must be angled — elements with two parallel surfaces are ''not'' prisms. The most familiar type of optical ...

or tabular in habit: they are usually colorless and transparent, and have a brilliant adamantine

lustre Lustre or Luster may refer to: Places * Luster, Norway, a municipality in Vestlandet, Norway ** Luster (village), a village in the municipality of Luster * Lustre, Montana, an unincorporated community in the United States Entertainment * ' ...

. Sometimes the crystals have a curious

helical Helical may refer to: * Helix A helix () is a shape like a corkscrew or spiral staircase. It is a type of smooth space curve with tangent lines at a constant angle to a fixed axis. Helices are important in biology, as the DNA molecule is for ...

twist about the tetrad or principal axis. The hardness is 3 and the specific gravity 6.3. The mineral is rather

sectile Sectility is the ability of a mineral to be cut into thin pieces with a knife. Minerals that are not sectile will be broken into rougher pieces when cut. Metals and paper are sectile. Sectility can be used to distinguish minerals of similar appea ...

, and consequently was earlier known as corneous lead, (German ''Hornblei'').

Name and occurrence

The name phosgenite was given by

August Breithaupt Johann Friedrich August Breithaupt (May 16, 1791 – September 22, 1873) was a German mineralogist and professor at Freiberg Mining Academy in Freiberg, Saxony. Biography He was born in Probstzella. He received his doctorate at the Universities ...

in 1820, from

phosgene Phosgene is the organic chemical compound with the formula COCl2. It is a toxic, colorless gas; in low concentrations, its musty odor resembles that of freshly cut hay or grass. Phosgene is a valued and important industrial building block, esp ...

, carbon oxychloride, because the mineral contains the elements carbon, oxygen and

chlorine Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is ...

. It was found associated with

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 ...

and matlockite in cavities within altered

galena Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver. Galena is one of the most abundant and widely distributed sulfide minerals. It cryst ...

in a lead mine at

Cromford Cromford is a village and civil parish in Derbyshire, England, in the valley of the River Derwent between Wirksworth and Matlock. It is north of Derby, south of Matlock and south of Matlock Bath. It is first mentioned in the 11th-century Do ...

, near Matlock: hence its common name cromfordite."Phosgenite and Matlockite in Derbyshire (Part 1). T. Bridges, M. E. Smith.
Journal of the Russell Society Volume 1, No. 2, p.7–14, 1983 Retrieved on 2011-01-11 Crystals are also found in galena at Monteponi near Iglesias in Sardinia, and near

Dundas Dundas may refer to: Places Australia * Dundas, New South Wales * Dundas, Queensland, a locality in the Somerset Region * Dundas, Tasmania * Dundas, Western Australia * Fort Dundas, a settlement in the Northern Territory 1824–1828 * Shire ...

in Tasmania. It has also been reported from Laurium, Greece; Tarnowitz, Poland; the Altai district, Siberia; the Touissit mine, near Oujda, Morocco; Sidi Amor ben Salem, Tunisia; Tsumeb, Namibia;

Broken Hill Broken Hill is an inland mining city in the far west of outback New South Wales, Australia. It is near the border with South Australia on the crossing of the Barrier Highway (A32) and the Silver City Highway (B79), in the Barrier Range. It i ...

, New South Wales; and Boleo, near

Santa Rosalía, Baja California Sur Santa Rosalía is a city and municipal seat of Mulegé Municipality, in Baja California Sur, situated along the Gulf of California. Located on the east coast of the Baja Peninsula, the town had a population of 14,160 inhabitants in 2015. The c ...

. In the US it has been reported from the Terrible mine,

Custer County, Colorado Custer County is a county located in the U.S. state of Colorado. As of the 2020 census, the population was 4,704. The county seat is Westcliffe. History Custer County was created by the Colorado legislature on March 9, 1877, out of the sout ...

; the Stevenson-Bennett mine, Organ Mountains,

Doña Ana County, New Mexico Doña Ana County is located in the southern part of the State of New Mexico, United States. As of the 2020 U.S. Census, its population was 219,561, which makes it the second-most populated county in New Mexico. Its county seat is Las Cruces, t ...

; and the Mammoth mine, Tiger, Pinal County, Arizona. Crystals of phosgenite, and also of the corresponding bromine compound PbBr₂CO₃, have been prepared artificially.

References

{{Refend Lead minerals Halide minerals Carbonate minerals Tetragonal minerals Minerals in space group 127 Luminescent minerals