Formula: AgCl
Chloride of silver, chlorargyrite group
Crystal System: Isometric
Specific gravity: 5.5 to 5.6 measured, 5.57 calculated
Hardness: 1½
Streak: White to grey
Colour: Colourless, white, yellowish, brownish, grey, black
Melts at 455°
Common impurities: I

Hydrothermal environments

Chlorargyrite is a secondary mineral found in the oxidation zone of silver deposits, especially in arid regions, and in epithermal (low temperature) veins. It is found associated with native silver, cerussite and other secondary minerals.


At the Broken Hill district, Yancowinna county, New South Wales, Australia, the deposit originally formed in a shallow lake or submarine rift and now comprises an intensely granulite and upper amphibolite facies metamorphosed and deformed sequence of sedimentary and volcanic rocks, and minor iron-rich and layers. Quartz-feldspar gneiss probably originated from felsic volcanic rocks and associated granitic intrusions, while amphibolites reflect metamorphosed mafic magmas originally emplaced as flows and associated intrusions. Subaqueous hydrothermal precipitation involving ore fluids from crustal, magmatic, evaporitic, and possibly lacustrine sources produced metal-rich deposits. Prolonged oxidation and weathering of the sulphide-rich orebodies in the near-surface environment produced a zone greatly enriched in silver and lead and many attractive, well-crystallised secondary minerals. This oxidised zone has long been removed by mining; current operations access the deeper, primary sulphide-rich orebodies (R&M 97.1.16-26).
Chlorargyrite occurs in vuggy coronadite with goethite, sometimes associated with smithsonite. It is also found with cerussite, dolomite and malachite. At deeper levels it is a late-stage mineral in the arsenate zones, associated with carminite and members of the segnitite to beudantite series (AJM 3.1.34).

Chlorargyrite from Broken Hill - Image

The type locality is the Marienberg mining district, Erzgebirgskreis, Saxony, Germany.

At the San Rafael Mine, Quartz Mountain camp, Lodi Mining District, Lodi Hills, Nye County, Nevada, USA, chlorargyrite and bromargyrite occur sparingly, associated with mimetite, anglesite and bayldonite (R&M 85.6.516).

Chlorargyrite from the San Rafael Mine - Image

At the Tintic Mining District, Juab County, Utah, USA, probably the most common silver mineral of the District, chlorargyrite, has been found in many of the mines, particularly where galena and other lead minerals are more common. At the Trixie mine in the East Tintic chlorargyrite occurs directly with hessite, native silver and native gold. It is most commonly found as brown smears that look like dirt; however, crystallized chlorargyrite has also been found at the Trixie mine.
At the nearby Tintic Standard mine, chlorargyrite rich in bromine has also been found, as solid masses up to 5 cm in size (MinRec 55.2.190-192).

Chlorargyrite from the Tintic Mining District - Image

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