Allanite-(La) (original) (raw)

A valid IMA mineral species

About Allanite-(La)Hide

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Formula:

(CaLa)(AlAlFe2+)O[Si2O7][SiO4](OH)

Colour:

Black, with brownish reflections

Crystal System:

Monoclinic

Name:

Named in 2006 by Paolo Orlandi and Marco Pasero for its relationship to other allanite group minerals, with lanthanum as the dominant rare earth element. The root name is for Thomas Allan (1777, Edinburgh, Scotland - 1833, Morpeth, Northumberland, England), Scottish banker and mineralogist who first described what is now allanite-(Ce). Samples fitting the description of allanite-(La) were described earlier and the name was recommended by Levinson (1966) but a proper species description was not given until 2006.

Allanite Group of the Epidote Supergroup. The La-analogue of Allanite-(Ce).

The large well formed crystals of "allanite-(La)" from the Nueva Vizcaya Mine, Spain published by Del Tanago et al. (2002) as “macroscopic La-dominant allanite and REE-rich epidote crystals” are zoned crystals containing allanite with Ce>La,allanite with La>Ce, and REE-rich epidote. Only thin zones within the crystals contain sufficient REE to qualify as allanite-(La), and the La dominant material were too scarce to adequately describe allanite-(La) as a new mineral.

Fleischer (1985) has studied analyses of 506 allanites and presents the average content of each of the REE elements (including Y) in various rock types:

Unique IdentifiersHide

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Long-form identifier:

mindat:1:1:126:3

a9c5bb3c-6812-424e-9b83-bd3a80cab66d

IMA Classification of Allanite-(La)Hide

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IMA Formula:

CaLa(Al2Fe2+)[Si2O7][SiO4]O(OH)

Classification of Allanite-(La)Hide

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9.BG.05b

9 : SILICATES (Germanates)
B : Sorosilicates
G : Sorosilicates with mixed SiO4 and Si2O7 groups; cations in octahedral [6] and greater coordination

58.2.1a.2

58 : SOROSILICATES Insular, Mixed, Single, and Larger Tetrahedral Groups
2 : Insular, Mixed, Single, and Larger Tetrahedral Groups with cations in [6] and higher coordination; single and double groups (n = 1, 2)

Mineral SymbolsHide

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As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.

Physical Properties of Allanite-(La)Hide

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Transparency:

Transparent, Translucent

Colour:

Black, with brownish reflections

Cleavage:

Imperfect/Fair
along {001}

Density:

3.93 g/cm3 (Measured) 3.94 g/cm3 (Calculated)

Optical Data of Allanite-(La)Hide

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RI values:

_n_α = 1.755 _n_β = 1.760 _n_γ = 1.765

δ = 0.010

Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.

Comments:

greenish to greenish brown

Chemistry of Allanite-(La)Hide

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Mindat Formula:

(CaLa)(AlAlFe2+)O[Si2O7][SiO4](OH)

Crystallography of Allanite-(La)Hide

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Crystal System:

Monoclinic

Class (H-M):

2/m - Prismatic

Cell Parameters:

a = 8.914 Å, b = 5.726 Å, c = 10.132 Å
β = 114.87°

Ratio:

a:b:c = 1.557 : 1 : 1.769

Morphology:

prismatic crystals, elongated along [010]
observed forms: {001}, {100}, {101}, {10_1}, {210} and {011}

Crystal StructureHide

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ID	Species	Reference	Link	Year	Locality	Pressure (GPa)	Temp (K)
0006069	Allanite-(La)	Orlandi P, Pasero M (2006) Allanite-(La) from Buca della Vena mine, Apuan Alps, Italy, an epidote-group mineral The Canadian Mineralogist 44 63-68		2006	Buca della Vena mine, near Stazzema, Apuan Alps, Tuscany, Italy	0	293

CIF Raw Data - click here to close

X-Ray Powder DiffractionHide

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Powder Diffraction Data:

Comments:

Format: d/Å (I/%) (hkl)

Geological EnvironmentHide

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Type Occurrence of Allanite-(La)Hide

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General Appearance of Type Material:

prismatic crystals up to 2–3 mm in length

Geological Setting of Type Material:

baryte veins cutting a dolomitic metamorphosed limestone

Synonyms of Allanite-(La)Hide

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Other Language Names for Allanite-(La)Hide

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Relationship of Allanite-(La) to other SpeciesHide

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Other Members of this group:

Common AssociatesHide

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Associated Minerals Based on Photo Data:

Related Minerals - Strunz-mindat GroupingHide

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Fluorescence of Allanite-(La)Hide

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Other InformationHide

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Health Risks:

No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

Internet Links for Allanite-(La)Hide

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References for Allanite-(La)Hide

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Localities for Allanite-(La)Hide

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This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.

Locality ListHide

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- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for references and further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.