Churchite-(Y)

churchite-(Y)

florencite

rhabdophane

goyazite

Images

Formula: Y(PO4).2H2O
Hydrated normal phosphate, yttrium-bearing mineral
Specific gravity: 3.14
Hardness: 3
Streak: White
Colour: Colourless, white, grey, yellow, colourless in transmitted light
Solubility: Soluble in hot acids, insoluble in alkalies
Environments

Carbonatites
Hydrothermal environments

Churchite-(Y) is typically derived from meteoric waters, with yttrium weathered or biochemically leached from trace amounts in surrounding rocks or soil, deposited on colloidal iron-manganese oxides; less commonly it occurs as a secondary mineral in hydrothermal mineral deposits. Associated minerals include florencite, rhabdophane, wavellite, crandallite, turquoise, variscite, cacoxenite, beraunite, dufrénite, goyazite, gorceixite, crandallite, monazite, apatite, todorokite, lithiophorite, hematite, limonite and clay minerals (HOM ).

Localities

At the Mount Weld mine, Mount Weld Station, Laverton Shire, Western Australia, churchite-(Y) occurs in carbonaceous laterite where it occurs as void fillings in crandallite group minerals, as fine grains, or intergrown with limonite and associated with goyazite, gorceixite, florencite, crandallite, monazite, apatite and cerianite (Dana).

The type locality is the Maffei Mine, Nitzlbuch, Auerbach in der Oberpfalz, Amberg-Sulzbach District, Upper Palatinate, Bavaria, Germany.

In Kazakhstan churchite-(Y) occurs in the mantle of weathered metamorphic rocks as crystallites up to 12 microns long associated with apatite, fluorite, amphiboles, and acicular transparent zeolites, possibly natrolite (Dana).

At Chuktukon carbonatite massif, Chadobets alkaline complex, Boguchansky District, Krasnoyarsk Krai, Russia, churchite-(Y) occurs in laterite (Dana).

At Wheal Pendarves, Killivose, Camborne, Cornwall, England, UK, churchite-(Y) is associated with limonite, quartz and baryte (Dana).

At the Kelly Bank mine, Lyndhurst-Vesuvius Mining District, Rockbridge county, Virginia, USA, specimens of manganiferous iron oxide were coated with minute specks of whitish radially fibrous aggregates of churchite-(Y), the largest less than a millimeter across, and characteristically coating brown siliceous limonite or black manganese oxide. The hemispherical rosettes frequently have a dusty brownish surface; many of them when broken show concentric black zones orcores of manganese dioxide (AM 29.92-107 {as Weinschenkite}).

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