Pohlite

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Formula: Pb₇(IO₃)(OH)₄Cl₉
Iodate
Crystal System: Triclinic
Specific gravity: 5.838 calculated for the empirical formula, 5.975 calculated for the ideal formula
Hardness: 2½
Streak: White
Colour: Colourless to pale grey
Luminescence: Not fluorescent under UV
Solubility: Pohlite becomes cloudy and very slowly dissolves in room-temperature, dilute hydrochloric acid
Environments

Hydrothermal

Pohlite is a new mineral, approved in 2022 and to date (April 2023) reported only from the type locality.

Localities

At the type locality, La Compañia Mine, Sierra Gorda, Antofagasta Province, Antofagasta, Chile, pohlite was found in a cavity of an oxidised portion of a quartz-baryte vein hosted by porphyritic andesites. The small blades of pohlite, up to 4 mm in length, are transparent and colourless. Associated Minerals include anhydrite, aragonite, boleite, cotunnite, goethite, gold, hematite, paratacamite, pseudoboleite, saponite and seeligerite.
The La Compañía mine is believed to have been in operation as early as the 16th century, and was one of the largest producers of silver in South America during the Spanish colonial period. In the 19th and early 20th centuries, the mine was modernised and expanded and continued to extract silver, gold, and other minerals. By the mid-20th century, the mine was largely depleted and was eventually closed (AM 108.4.784, Mindat).

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