Formula: K6Fe24S26Cl
Sulphide, approved in 2000
Specific gravity: 3.7
Hardness: 4
Streak: Black
Colour: Brown, black

Hydrothermal environments


The type locality is the Koashva Open Pit, Koashva Mountain, Khibiny Massif, Murmansk Oblast, Russia. This is an apatite deposit that works part of an alkaline massif with ultra-agpaitic pegmatites and urtite, as well as foidolites and apatite-nepheline rocks with aegirine-microcline, aegirine-nepheline-microcline, and titanite-aegirine-nepheline veins, and olivine metamorphosed nephelinite dykes (Mindat).

Chlorbartonite occurs in a microclinepectolitesodaliteaegirine hydrothermal vein. The host rocks are massive urtite. Lens-shaped bodies of apatitetitanite rock are dominant. The vein containing chlorbartonite is located near the contact between apatitenepheline rocks and urtite. The chlorbartonite occurs as inclusions within sodalite and natrolite.

The marginal zone consists of microcline, nepheline, sodalite and dark red villiaumite. The villiaumite contains inclusions of lomonosovite, pectolite, aegirine, arfvedsonite, thermonatrite and chkalovite. Small crystals of lisitsynite also are present.

The intermediate zone is composed of snow-white, radiating crystals of pectolite with interstitial villiaumite.

The border between the zones is marked by extremely large lenses of dark red villiaumite also containing white aggregates of acicular pectolite, dark grey spherulites of lomonosovite, light pink or light green crystals of sodalite, annite, pseudomorphs of nefedovite together with sidorenkite and lorenzenite after an unknown mineral, nacaphite, vitusite-(Ce), colourless crystals of chkalovite, light green microcline, yellowish green fluorcaphite, galena, cobaltite, dark brown sphalerite, dark green fibrous nodules of aegirine, golden brown astrophyllite and ice-like translucent grains of natrite.
When exposed to weathering, the natrite grains become covered with a crust of fine-grained thermonatrite and trona. Small crystals of rasvumite, black-brown grains of chlorbartonite, green burbankite, mosandrite-(Ce), and grains of djerfisherite and sphalerite occur as inclusions within light pink sodalite and light grey natrolite. Clusters of crystals of murunskite and well-formed cubic crystals of loparite-(Ce) occur at borders between villiaumite and microcline, sodalite and lomonosovite. Apple-green grains and well-formed crystals of fluorcaphite and also grains of light brown sphalerite are common within the large blocks of villiaumite.

The core zone of the vein is formed of nodules of acicular aegirine with inclusions of lamprophyllite and lomonosovite, and cemented by villiaumite. Vitusite-(Ce), nacaphite, thorosteenstrupine-(Ce), natrophosphate, galena, mackinawite, djerfisherite and lemmleinite-K have also been observed in this zone. Chlorbartonite is a low-temperature hydrothermal mineral; it crystallised together with djerfisherite, rasvumite, natrolite and sodalite during the latest stages of hydrothermal activity
(CM 41.503-511).

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