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Almandine

Big Photo

Wrangell, Wrangell Island, Wrangell-Petersburg Borough, Alaska, USA
© 2002 John H. Betts

Show Almandine Photos (372)
Formula:
Fe
2+
3
Al
 
2
[SiO
 
4
]
 
3
System:IsometricColour:Brown, brownish red, ...
Lustre:Vitreous, ResinousHardness:7 - 7½
Name:For Albanda in Turkey, ancient gem cutting center.


Garnet Group. Almandine-Pyrope Series, Almandine-Spessartine Series.

Most common garnet. Occurs in metamorphic and pegmatitic rocks.

Classification of Almandine

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:8/A.08-20
Nickel-Strunz 10th (pending) edition ID:9.AD.25

9 : SILICATES (Germanates)
A : Nesosilicates
D : Nesosilicates without additional anions; cations in [6] and/or greater coordination
Dana 8th edition ID:51.4.3a.2

51 : NESOSILICATES Insular SiO4 Groups Only
4 : Insular SiO4 Groups Only with cations in [6] and >[6] coordination
Hey's CIM Ref.:16.17.1

16 : Silicates Containing Aluminum and other Metals
17 : Aluminosilicates of Fe
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Type Occurrence of Almandine

Type Locality:Alabanda, Aydin Province, Aegean Region, Turkey

Occurrences of Almandine

Geological Setting:Mica schists and gneisses, metamorphism of pelitic sedimentary rocks. Contact metamorphic hornfels, eclogites, granites.

Physical Properties of Almandine

Lustre:Vitreous, Resinous
Diaphaneity (Transparency):Transparent, Translucent
Colour:Brown, brownish red, red, black, or black red
Streak:White
Hardness (Mohs):7 - 7½
Tenacity:Brittle
Parting:On {110}
Fracture:Sub-Conchoidal
Density (measured):4.318 g/cm3
Density (calculated):4.313 g/cm3

Crystallography of Almandine

Crystal System:Isometric
Class (H-M):m3m (4/m 3 2/m) - Hexoctahedral
Space Group:Ia3d (I41/a 3 2/d)
Cell Parameters:a = 11.526Å
Unit Cell Volume:V 1,531.21 ų (Calculated from Unit Cell)
Z:8
Morphology:Dodecahedra or trapezohedra.
X-Ray Powder Diffraction:
Image Loading

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

Optical Data of Almandine

Type:Isotropic
RI values: n = 1.83
Maximum Birefringence:δ = 0.000 - Isotropic minerals have no birefringence
Surface Relief:Very High
Comments:Anomalously biaxial.

Chemical Properties of Almandine

Formula:
Fe
2+
3
Al
 
2
[SiO
 
4
]
 
3
Essential elements:Al, Fe, O, Si
All elements listed in formula:Al, Fe, O, Si

Relationship of Almandine to other Species

Series:Forms a series with Pyrope (see here)
Forms a series with Spessartine (see here)
Member of:Garnet Group
Related Minerals - Nickel-Strunz Grouping):
9.AD.05Larnite
Ca
 
2
[SiO
 
4
]
9.AD.05Calcio-Olivine
Ca
 
2
[SiO
 
4
]
9.AD.15Merwinite
Ca
 
3
Mg[SiO
 
4
]
 
2
9.AD.20Bredigite
Ca
 
7
Mg[SiO
 
4
]
 
4
9.AD.25Andradite
Ca
 
3
Fe
3+
2
[SiO
 
4
]
 
3
9.AD.25Calderite
(Mn
2+
 
,Ca)
 
3
(Fe
3+
 
,Al)
 
2
[SiO
 
4
]
 
3
9.AD.25Goldmanite
Ca
 
3
(V
3+
 
,Al,Fe
3+
 
)
 
2
[SiO
 
4
]
 
3
9.AD.25Grossular
Ca
 
3
Al
 
2
[SiO
 
4
]
 
3
9.AD.25Henritermierite
Ca
 
3
(Mn
3+
 
,Al)
 
2
[(OH)
 
4
|(SiO
 
4
)
 
2
]
9.AD.25Hibschite
Ca
 
3
Al
 
2
[(OH)
 
6-1
|(SiO
 
4
)
 
1.5-2.5
]
9.AD.25Hydroandradite
9.AD.25Katoite
Ca
 
3
Al
 
2
[(OH)
 
8-6
|(SiO
 
4
)
 
1-1.5
]
9.AD.25Kimzeyite
Ca
 
3
(Zr,Ti)
 
2
[(Si,Al,Fe
3+
 
)O
 
4
]
 
3
9.AD.25Knorringite
Mg
 
3
Cr
 
2
[SiO
 
4
]
 
3
9.AD.25Majorite
Mg
 
3
(Fe
2+
 
,Si,Al)
 
2
[SiO
 
4
]
 
3
9.AD.25Morimotoite
Ca
 
3
(Ti,Fe
2+
 
,Fe
3+
 
)
 
2
[(Si,Fe
3+
 
)O
 
4
]
 
3
 (?)
9.AD.25Pyrope
Mg
 
3
Al
 
2
[SiO
 
4
]
 
3
9.AD.25Schorlomite
Ca
 
3
(Ti,Fe
3+
 
)
 
2
[(Si,Fe
3+
 
,Fe
2+
 
)O
 
4
]
 
3
9.AD.25Spessartine
Mn
2+
3
Al
 
2
[SiO
 
4
]
 
3
9.AD.25Uvarovite
Ca
 
3
Cr
 
2
[SiO
 
4
]
 
3
9.AD.25Wadalite
Ca
 
6
(Al,Mg)
 
4
[Cl
 
3
|O
 
4
|{(Si,Al,Fe
3+
 
)O
 
4
}
 
3
]
9.AD.25Holtstamite
Ca
 
3
(Al,Mn
3+
 
)
 
2
(SiO
 
4
)
 
2
(OH)
 
4
9.AD.30Coffinite
(U,Th)[(OH)
 
4x
|(SiO
 
4
)
 
1-x
]
9.AD.30Hafnon
(Hf,Zr)[SiO
 
4
]
9.AD.30Thorite
(Th,U)[SiO
 
4
]
9.AD.30Thorogummite
(Th,U)[(OH)
 
4x
|(SiO
 
4
)
 
1-x
]
9.AD.30Zircon
Zr[SiO
 
4
]
9.AD.35Huttonite
Th[SiO
 
4
]
9.AD.35Tombarthite-(Y)
Y
 
4
[HSiO
 
4
]
 
3
9.AD.40Eulytine
Bi
 
4
[SiO
 
4
]
 
3
9.AD.45Reidite
Zr[SiO
 
4
]
Related Minerals - Hey's Index Grouping:
16.17.2Macaulayite
(Fe,Al)
 
24
Si
 
4
O
 
43
(OH)
 
2

Other Names for Almandine

Synonyms:
Adelaide-rubinAdelaide rubyAlabandine RubyAlamandineAlmandine Garnet
AlmandinoAlmanditeOriental Garnet
German names:
Almandit
Latin names:
Alabandicus (of Pliny)
Russian names:
Альмандин
Spanish names:
Almandita
Varieties:
DhanrasiteStar Garnet

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.
Industrial Uses:Abrasive.

References for Almandine

Reference List:Rossman, G.R., Rauch, F., Livi, R., Tombrello, T.A., Shi, C.R., and Zhoi, Z.Y. (1988) Nuclear reaction analysis of hydrogen in almandine, pyrope and spessartine garnets. Neues Jahrbuch für Mineralogie Monatshefte: 4: 172-178.

American Mineralogist (1992): 77: 512-521.

Wang, L., Essene, E.J., and Zhang, Y. (2000) Direct observation of immiscibility in pyrope-almandine-grossular garnet. American Mineralogist: 85: 41-46.

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    Localities for Almandine

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