Allanite-(La)

allanite-(La)

zircon

apatite

epidote

Images
Formula: CaLa(Al2Fe2+)[Si2O7][SiO4]O(OH)
Sorosilicate (Si2O7 groups), allanite group of the epidote supergroup, lanthanum-bearing mineral
Crystal System: Monoclinic
Specific gravity: 3.93 measured, 3.94 calculated
Hardness: 6
Streak: Brown
Colour: Black, with brownish reflections
Luminescence: Not fluorescent under UV
Solubility:
Environments

Plutonic igneous environments
Pegmatites
Metamorphic environments

Localities

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) is closely associated with calcite and baryte, and occurs within baryte veins cutting a dolomitic metamorphosed limestone in a specific zone of the mine known as “Castello”. The Buca della Vena mine is a well-known small mineralised orebody of microcrystalline hematite, magnetite, pyrite and baryte. At this locality, tiny black prismatic crystals of allanite-(Ce) were also found in other quartz veins located in a different part of the mine; allanite-(Ce) occurs there together with monazite-(Ce), pyrite, anatase, gypsum and diadochite (CM 44.1.63-68).

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).

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