Sorosilicates (Si2O7 groups), epidote group and form a complete solid solution series with it.
Specific gravity: allanite-(Ce) 3.4 to 4.2; allanite-(La) 3.69 to 4.02
Hardness: allanite-(Ce) 5 to 6½ allanite-(La) 5 to 5½ allanite-(Y) 6
Streak: allanite-(Ce) light brown
Colour: allanite-(Ce) light brown to black
Solubility: allanite-(Ce) gelatinises with hydrochloric acid Dana
Common impuritiesin allanite-(Nd): Al,Ca,Ce,Fe,La,Mg,Mn,Pr,Sm,Ti
Plutonic igneous environments
The allanite minerals are sorosilicates containing the rare earth elements cerium Ce, lanthanum La, neodymium Nd and yttrium Y, and
are often metamict. Allanites are a common accessory mineral in granite,
syenite, and granitic pegmatite. They
are also found in diorite and gabbro,
as phenocrysts in acidic volcanic rocks, and in a number of metamorphic rock types (R&M 86.5.450).
At Pacoima Canyon, Los Angeles County, California, USA, allanite occurs with zircon and apatite in a pegmatite (AM 56.447).
Allanite-(Ce) is an accessory mineral in some granites and granite pegmatites and syenites, and more rarely in gabbroic pegmatites; it occurs rarely in schist, gneiss and some contact metamorphosed limestones, and it can be a detrital mineral (Dana, HOM). Associated minerals include epidote, muscovite and fluorite (HOM, Mindat).
The type locality for allanite-(Ce) is Qáqarssuatsiaq, Aluk Island, Kujalleq, Greenland, Denmark.
At the Trimouns quarry, Ariège, France, allanite-(Ce) is found in dolomite and talc, and may be associated with bastnäsite, synchysite, parisite, quartz, calcite, and very rarely hingganite (R&M 35.3.232, R&M 86.5.451).
At the Bastnas mines, Vastmanland, Sweden, allanite-(Ce) occurs within amphibole skarn and as compact masses with cerite-(Ce). Associated minerals include chalcopyrite, bismuthinite, bastnäsite and rarely linnaeite (R&M 35.3.193-194).
At the Tiro Estrella mine, Lincoln County, New Mexico, USA, allanite-(Ce) occurs in quartz veins with feldspar.
At the Dafoe Property, Pierrepont, St Lawrence county, New York, USA, allanite-(Ce) occurs as inclusions in late-stage quartz crystals (R&M 94.5.452-455).
At Power's Farm, Pierrepont, St. Lawrence county, New York, USA, allanite-(Ce) occurs as a late-stage mineral associated with microcline, quartz, and chamosite (R&M 85.2.162).
At the danburite occurrence near Russell, St. Lawrence county, New York, USA, allanite-(Ce) forms crystals on tremolite (R&M 90.3.217).
At the Selleck Road Locality, West Pierrepont, St. Lawrence county, New York, USA, allanite-(Ce), or a closely related species, occurs on the surfaces of microcline crystals (R&M 91.2.121).
In New York city, New York, USA, an allanite-(Ce) crystal has been found at the southeast corner of 56th and Broadway embedded in albite pegmatite, and another allanite-(Ce) crystal has been found embedded in quartz from the Brooklyn-Battery Tunnel (R&M 84.3.221-222).
At Serifos island, Cyclades, Greece, allanite-(La) occurs in skarn (Dana).
At the type locality, the Buca della Vena Mine, Stazzema, Lucca Province, Tuscany, Italy allanite-(La) occurs in baryte veins cutting a dolomitic metamorphosed limestone (Mindat, R&M 86.5.451, Webmin, HOM), associated with calcite and baryte (HOM).
At the Nueva Vizcaya mine, Badajoz, Spain, crystals of allanite-(La) occur in skarn associated with magnetite, actinolite, albite, epidote, and titanite (R&M 86.5.451). Although allanite-(La) is very rare generally, it is relatively common on a particular part of the dump at the Nueva Vizcaya mine, embedded in calcite (Min Rec 33-6.491-494).
At the type locality, the Åskagen Quarry, Filipstad, Värmland, Sweden, allanite-(Nd) occurs as aggregates within altered thalénite-(Y). Associated minerals include iimoriite-(Y), keiviite-(Y), allanite-(Y) and tengerite-(Y) (AM 97.983-988).
Allanite-(Y) was originally described from the Zaaiplaats tin mine, Potgietersrust district, Transvaal, South Africa. It occurs in an explosion breccia in a cassiterite-bearing pipe in granite, in hydrothermally altered arkoses, and in granitic pegmatite (Dana).
At the Longs Peak - St Vrain batholith near Jamestown, Jamestown District, Boulder county, Colorado, USA, centimetre to decimetre sized mineralised pods and veins consist of zoned mineral assemblages dominated by fluorbritholite-(Ce) in a core 10 cm thick, with monazite-(Ce), fluorite and minor quartz, uraninite and sulphides. The core is surrounded by a typically millimetre thick rim of allanite-(Ce), with minor monazite-(Ce) in the inner part of the rim. Bastnäsite-(Ce), törnebohmite-(Ce) and cerite-(Ce) appear in an intermediate zone between core and rim, often just a few hundreds of microns wide (R&M 96.3.252-253).
Back to Minerals