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Andesine

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Formula:
(Na,Ca)[Al(Si,Al)Si
 
2
O
 
8
]
System:TriclinicColour:White, gray, green, ...
Lustre:Sub-Vitreous, PearlyHardness:6 - 6½
Member of:Feldspar Group
Name:For the Andes Mountains of South America where it is abundant in the lavas.
A variety of Albite

A plagioclase feldspar with an albite : anorthite molar ratio ranging from 50 : 50 to 70 : 30.

Originally described from Marmato Mine, Marmato, Cauca, Chocó Department, Colombia.
Crystals rare, to 2 cm; commonly massive, cleavable, or granular. Twinning: Commonly twinned after Albite, Pericline, and Carlsbad laws. Also twinned after a law similar to the Manebach law.

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Classification of Andesine

Strunz 8th edition ID:8/J.07-40
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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Occurrences of Andesine

Geological Setting:Widespread in igneous rocks of intermediate silica content, as syenites and andesites. Characteristic of granulite to amphibolite facies metamorphism, commonly as antiperthite; as detrital grains in sedimentary rocks.

Physical Properties of Andesine

Lustre:Sub-Vitreous, Pearly
Diaphaneity (Transparency):Transparent, Translucent
Colour:White, gray, green, yellow, flesh-red.
Streak:White
Hardness (Mohs):6 - 6½
Tenacity:Brittle
Cleavage:Perfect
Perfect on {001}, less perfect on {010}; {110} also observed.
Fracture:Irregular/Uneven, Conchoidal

Crystallography of Andesine

Crystal System:Triclinic

Optical Data of Andesine

Type:Biaxial (+/-)
RI values: nα = 1.543 - 1.554 nβ = 1.547 - 1.559 nγ = 1.552 - 1.562
2V:Measured: 76° to 83°, Calculated: 78° to 84°
Maximum Birefringence:δ = 0.009

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 Andesine

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

Relationship of Andesine to other Species

Member of:Feldspar Group
Other Members of Group:

- +
Albite
NaAlSi
 
3
O
 
8
Amazonite
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
]
Labradorite
(Ca,Na)[Al(Al,Si)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
Common Associates:
QuartzMagnetiteK FeldsparHornblendeBiotite
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.35Anorthite
CaAl
 
2
Si
 
2
O
 
8
9.FA.35Bytownite
(Ca,Na)[Al(Al,Si)Si
 
2
O
 
8
]
9.FA.35Labradorite
(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 Andesine

Synonyms:
Andesite (of Dana)
Other Languages:
German:Andesin
Russian:Андезин
Simplified Chinese:中性长石
中长石

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 Andesine

Reference List:

- +
Richet, P. and Bottinga, Y. (1984b) Anorthite, andesine, wollastonite, diopside, cordierite, and pyrope thermodynamics of melting, glass transitions, and properties of the amorphous phases. Earth and Planetary Science Letters: 67: 415-432.

Internet Links for Andesine

Search Engines:
  • Look for Andesine on Google
  • Look for Andesine images on Google
  • External Links:
  • Andesine details from Handbook of Mineralogy (PDF)
  • Mineral Dealers:
  • Rare and Unusual minerals at Mineralogical Research Company
  • Andesine specimens for sale - minfind.com
  • High-end worldwide specimens & outstanding customer service
  • Fine Minerals from Weinrich Minerals, Inc.
  • rare and unusual minerals mainly crystallized
  • Buy from McDougall Minerals
  • Fine and rare minerals from mintreasure.com
  • Lapis Mineral Magazin
  • Find Andesine on www.crystalclassics.co.uk
  • Wilensky Fine Minerals
  • Buy from David K Joyce minerals
  • Fabre Minerals - search for Andesine specimens
  • Specimens:The following Andesine specimens are currently listed for sale on minfind.com.

    Localities for Andesine

    The 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.
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