Cloudite

cloudite

gorceixite

beudantite group

barium

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Formula: BaFe3+3(PO4)(SO4)(OH)6
Valence: BaF3+3(PO4)(S6+O4)(OH)6
Phosphate, beudantite group, alunite supergroup, barium-bearing mineral
Crystal system: Trigonal
Streak: Yellow
Colour: Orange
Environments

Sedimentary environments
Hydrothermal environments

Cloudite is a new mineral, approved in 2023 and to date (Januaty 2026) reported only from the type locality.

Localities

At the type locality, 180 level, Iron Monarch Main Pit, Iron Knob, Pastoral Unincorporated Area, South Australia, the iron ore deposits are hosted by a sequence of chemical metasediments. The iron ore mineralisation was formed primarily by supergene enrichment of an iron formation involving dissolution of gangue minerals and partial, or total, replacement of magnetite by hematite. The orebody contains pods of high-grade manganese ore, and the presence of iron and manganese with small amounts of copper, zinc, bismuth, silver, phosphorous, arsenic and other elements has led to an unusually diverse mineralogy, formed as a result of weathering.
Alunite supergroup minerals, including alunite, crandallite, gorceixite, hidalgoite, jarosite, kintoreite, natrojarosite and plumbojarosite, have been found throughout the quarry. Gorceixite was a common mineral in a zone of a siliceous banded ironstone on the 180 level of the quarry.
Cloudite has been found on several specimens collected from this zone in the 1990s. It occurs in seams in a matrix composed of quartz and hematite, and associated with gorceixite, fluorapatite and baryte.
The cloudite forms orange tabular to equant crystals up to 40 microns across that show minor to significant compositional zonation (CJMP 64.95-104).

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