Carbocernaite

carbocernaite

chlorite

ankerite

alstonite

Images

Formula: (Sr,Ce,La)(Ca,Na)(CO3)2
Anhydrous normal carbonate, strontium-, cerium- and lanthanum- bearing mineral
Crystal System: Orthorhombic
Specific gravity: 3.33 to 3.45 measured, 3.53 calculated
Hardness: 3
Streak: White
Colour: Colourless; white, yellow, yellowish green, rose or brown if altered
Solubility: Easily soluble in dilute hydrochloric acid
Weakly RADIOACTIVE
Environments

Carbonatites

Localities

At the Central Khanneshin deposit, Khanneshin complex, Reg District, Helmand, Afghanistan, carbocernaite is associated with dolomite, baryte, chlorite, mckelveyite-(Y), calkinsite-(Ce) and khanneshite (HOM).

At the Sturgeon Narrows Alkaline Complex, Squash Lake Area, Kenora District, Ontario, Canada, carbocernaite has been identified from the east side of the Narrows. Data for carbocernaite from this locality this are in close agreement with the data published for carbocernaite from the type locality in the Kola Peninsula, but this carbocernaite contains significant amounts of fluorine, is a more strontium-rich variety and contains no sodium or barium.
Carbocernaite occurs as distinct layers and clusters in an albite - biotite - calcite carbonatite. The mineral is closely associated with purple fluorite and calcite and together they give the rock a definite gneissic appearance. The layers of carbocernaite are even more distinct on the weathered surface because the mineral is more resistant to weathering than the surrounding calcite. Associated minerals include pyrite, quartz, baryte, galena, chalcopyrite and minor amounts of ancylite. The carbocernaite varies from pale pink to brick red in colour, due to admixed iron oxide in the mm-sized grains (CM 11.812-818).

At Sarnu-Dandali, Malani Igneous Province, Barmer District, Jodhpur Division, Rajasthan, India, carbocernaite occurs exsolved from calcite and in a carbonatite dike in fenitised dark-coloured nephelinite (HOM).

At the Carbonatite Stock in the vicinity of Tul'ilukht Bay, Khibiny Massif, Murmansk Oblast, Russia, hexagonal prismatic pseudomorphs of ancylite-(Ce) or synchysite-(Ce), strontianite and baryte after burbankite and carbocernaite occur (MM 62.2.225-250).

At the type locality, the Vuoriyarvi alkaline-ultrabasic massif, Northern Karelia, Murmansk Oblast, Russia, carbocernaite occurs in dolomite - calcite carbonatite veins 0.5 to 1 m in width, in pyroxenites and ijolites, as accessory grains and as crystals on walls of cavities, closely associated with chlorite and ankerite. Other associated minerals include sphalerite, galena, pyrite and baryte, and in the cavities alstonite, anatase, quartz and zeolites (AM 46.1202). At Bear Lodge Mining District, Crook County, Wyoming, USA, zoned crystals of carbocernaite occur in hydrothermally reworked burbankite- and fluorapatite- bearing calcite carbonatite. The carbocernaite is paragenetically associated with pyrite, strontianite, baryte, ancylite-(Ce) and late-stage calcite. It is assumed to have precipitated from sulphate-bearing fluids derived from an external source and enriched in sodium, calcium, strontium, barium and rare-earth elements through dissolution of the primary calcite and burbankite.
The crystals of carbocernaite show complex zoning patterns arising from significant variations in the content of all major cations (AM 102.1340-1352).

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