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Labradorite

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Formula:
(Ca,Na)[Al(Al,Si)Si
 
2
O
 
8
]
Colour:Pale green, blue, ...Hardness:6 - 6½
Member of:Feldspar Group
Name:From the occurrence at Ford Harbour, Paul Island,Labrador, Canada (Nain anorthosite).
A variety of Anorthite

A plagioclase feldspar with an albite : anorthite molar ratio ranging from 30 : 70 to 50 : 50.
An intermediate member of the Albite-Anorthite Series.

Originally found at Ford Harbour, Paul Island, near Nain, off the east coast of Labrador, Newfoundland and Labrador [56° 30' N, 61° 30' W].


Visit gemdat.org for gemological information about Labradorite. Currently in public beta-test.

Classification of Labradorite

Strunz 8th edition ID:8/J.07-50
Nickel-Strunz 10th (pending) edition ID:9.FA.35

9 : SILICATES (Germanates)
F : Tektosilicates without zeolitic H2O
A : Tektosilicates without additional non-tetrahedral anions
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Physical Properties of Labradorite

Lustre:Sub-Vitreous
Colour:Pale green, blue, colourless, grey-white
Streak:White
Hardness (Mohs):6 - 6½
Cleavage:Perfect
X-Ray Powder Diffraction:
Image Loading

Radiation - Copper Kα
Data Set:
Horizontal Axis: ° to ° Vertical Axis: % Source Data: Filtered Data:
Data courtesy of RRUFF project at University of Arizona, used with permission.

Optical Data of Labradorite

Type:Biaxial (+)
RI values: nα = 1.554 - 1.563 nβ = 1.559 - 1.568 nγ = 1.562 - 1.573
2V:Measured: 85° , Calculated: 78° to 86°
Maximum Birefringence:δ = 0.008 - 0.010

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Low
Dispersion:none

Chemical Properties of Labradorite

Formula:
(Ca,Na)[Al(Al,Si)Si
 
2
O
 
8
]
Simplified for copy/paste:(Ca,Na)[Al(Al,Si)Si2O8]
Essential elements:Al, Ca, O, Si
All elements listed in formula:Al, Ca, Na, O, Si

Relationship of Labradorite to other Species

Member of:Feldspar Group
Other Members of Group:

- +
Albite
NaAlSi
 
3
O
 
8
Amazonite
Andesine
(Na,Ca)[Al(Si,Al)Si
 
2
O
 
8
]
Anorthite
CaAl
 
2
Si
 
2
O
 
8
Anorthoclase
(Na,K)AlSi
 
3
O
 
8
Banalsite
BaNa
 
2
[Al
 
2
Si
 
2
O
 
8
]
 
2
Buddingtonite
(NH
 
4
)AlSi
 
3
O
 
8
Bytownite
(Ca,Na)[Al(Al,Si)Si
 
2
O
 
8
]
Celsian
BaAl
 
2
Si
 
2
O
 
8
Dmisteinbergite
CaAl
 
2
Si
 
2
O
 
8
Hyalophane
(K,Ba)[Al(Si,Al)Si
 
2
O
 
8
]
Microcline
KAlSi
 
3
O
 
8
Oligoclase
(Na,Ca)[Al(Si,Al)Si
 
2
O
 
8
]
Orthoclase
KAlSi
 
3
O
 
8
Paracelsian
BaAl
 
2
Si
 
2
O
 
8
Reedmergnerite
Na[BSi
 
3
O
 
8
]
Sanidine
KAlSi
 
3
O
 
8
Slawsonite
(Sr,Ca)Al
 
2
Si
 
2
O
 
8
Stronalsite
SrNa
 
2
[Al
 
2
Si
 
2
O
 
8
]
 
2
Svyatoslavite
CaAl
 
2
Si
 
2
O
 
8
Related Minerals - Nickel-Strunz Grouping):

- +
9.FA.05Kaliophilite
KAlSiO
 
4
9.FA.05Kalsilite
KAlSiO
 
4
9.FA.05Nepheline
(Na,K)AlSiO
 
4
9.FA.05Panunzite
(K,Na)AlSiO
 
4
9.FA.05Trikalsilite
(K,Na)AlSiO
 
4
9.FA.05Yoshiokaite
(Ca,Na)[Al(Al,Si)O
 
4
]
9.FA.05Megakalsilite
KAlSiO
 
4
9.FA.10Malinkoite
NaBSiO
 
4
9.FA.15Virgilite
LiAlSi
 
2
O
 
6
9.FA.25Lisitsynite
KBSi
 
2
O
 
6
9.FA.30Adularia
KAlSi
 
3
O
 
8
9.FA.30Anorthoclase
(Na,K)AlSi
 
3
O
 
8
9.FA.30Buddingtonite
(NH
 
4
)AlSi
 
3
O
 
8
9.FA.30Celsian
BaAl
 
2
Si
 
2
O
 
8
9.FA.30Hyalophane
(K,Ba)[Al(Si,Al)Si
 
2
O
 
8
]
9.FA.30Microcline
KAlSi
 
3
O
 
8
9.FA.30Orthoclase
KAlSi
 
3
O
 
8
9.FA.30Sanidine
KAlSi
 
3
O
 
8
9.FA.30Rubicline
(Rb,K)AlSi
 
3
O
 
8
9.FA.30Monalbite
NaAlSi
 
3
O
 
8
9.FA.35Albite
NaAlSi
 
3
O
 
8
9.FA.35Andesine
(Na,Ca)[Al(Si,Al)Si
 
2
O
 
8
]
9.FA.35Anorthite
CaAl
 
2
Si
 
2
O
 
8
9.FA.35Bytownite
(Ca,Na)[Al(Al,Si)Si
 
2
O
 
8
]
9.FA.35Oligoclase
(Na,Ca)[Al(Si,Al)Si
 
2
O
 
8
]
9.FA.35Reedmergnerite
Na[BSi
 
3
O
 
8
]
9.FA.40Paracelsian
BaAl
 
2
Si
 
2
O
 
8
9.FA.45Svyatoslavite
CaAl
 
2
Si
 
2
O
 
8
9.FA.45Kumdykolite
NaAlSi
 
3
O
 
8
9.FA.50Slawsonite
(Sr,Ca)Al
 
2
Si
 
2
O
 
8
9.FA.55Lisetite
CaNa
 
2
Al
 
4
Si
 
4
O
 
16
9.FA.60Banalsite
BaNa
 
2
[Al
 
2
Si
 
2
O
 
8
]
 
2
9.FA.60Stronalsite
SrNa
 
2
[Al
 
2
Si
 
2
O
 
8
]
 
2
9.FA.65Danburite
CaB
 
2
Si
 
2
O
 
8
9.FA.65Maleevite
BaB
 
2
Si
 
2
O
 
8
9.FA.65Pekovite
SrB
 
2
Si
 
2
O
 
8
9.FA.70Lingunite
(Na,Ca)AlSi
 
3
O
 
8
9.FA.75Kokchetavite
KAlSi
 
3
O
 
8

Other Names for Labradorite

Synonyms:
Black MoonstoneCarnatiteLabrador FeldsparLabrador MoonstoneMauilite
Opaline FeldsparRadauiteSiliciteSpectrolite
Other Languages:
Czech:Labradorit
Dutch:Labradoriet
Finnish:Labradoriitti
French:Labradorite
German:Labradorit
Carnatit
Mauilit
Radauit
Silicit
Spectrolith
Spektrolith
Hebrew:לברדוריט
Italian:Labradorite
Japanese:ラブラドル長石
Lithuanian:Labradoritas
Norwegian (Bokmål):Labrador
Polish:Labrador
Portuguese:Labradorite
Russian:Лабрадорит
Simplified Chinese:拉长石
变彩拉长石
Slovak:Labradorit
Spanish:Labradorita
Carnatita
Mauilita
Radauita
Silicita
Spectrolita
Ukrainian:Лабрадорит
Varieties:
Lynx Eye

Other Information

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

References for Labradorite

Reference List:

- +
Rose. G. (1823): Über den Feldspat, Albit, Labradorit und Anorthit, Annalen der Physik und Chemie, Vol. 73/NF-43, 175-208.

Acta Crystallographica (1988): B44: 344.

http://rruff.info/doclib/hom/labradorite.pdf

Internet Links for Labradorite

Search Engines:
  • Look for Labradorite on Google
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  • External Links:
  • Labradorite details from Handbook of Mineralogy (PDF)
  • Mineral Dealers:
  • Find Labradorite on www.crystalclassics.co.uk
  • The Arkenstone - Fine Minerals
  • SpiriferMinerals.com - high quality low prices
  • Labradorite specimens for sale - minfind.com
  • Mineral Classics - Worldwide Collector Quality Minerals and Gems
  • Buy from McDougall Minerals
  • Fine and rare minerals from mintreasure.com
  • Fabre Minerals - search for Labradorite specimens
  • Lapis Mineral Magazin
  • Top quality minerals from Kristalle of California
  • rare and unusual minerals mainly crystallized
  • Search for Labradorite on Well-Arranged Molecules
  • Specimens:The following Labradorite specimens are currently listed for sale on minfind.com.
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  • Localities for Labradorite

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