Fe2+
3 Al2 (SiO4 )3Almandine
c 2001 Mineral Data Publishing, version 1.2°

Crystal Data: Cubic. Point Group: 4=m 3 2=m: Typically well-formed dodecahedra ortrapezohedra, to 1 m; also in rounded grains and massive.
Physical Properties:
Cleavage: Parting on f110g. Fracture: Subconchoidal.
Tenacity: Brittle. Hardness = 7{7.5 D(meas.) = 4.318 D(calc.) = 4.313
Optical Properties: Transparent to translucent. Color: Deep red, brownish red, red-violet,black; may be sectored. Streak: White. Luster: Vitreous to resinous.
Optical Class: Isotropic; anomalously biaxial. Dispersion: Weak. n = 1.830
Cell Data:

Space Group: Ia3d: a = 11.526

Z=8X-ray Powder Pattern: Cavendish Township, Peterborough Co., Ontario, Canada. (ICDD9-427).
2.569 (100), 1.540 (50), 2.873 (40), 1.599 (40), 4.04 (30), 1.866 (30), 1.660 (30)
Chemistry:
SiO2TiO2
Al2 O3Fe2 O3FeO
MnO
MgO
CaO

(1)
37.39
0.16
20.72
0.83
36.37
0.86
3.85
0.41

(2)
36.21

Total

100.59100.00

20.49
43.30

3+(1) Falun, Sweden; corresponds to (Fe2+2:49 Mn0:14 Ca0:05 )§=2:68 (Al1:94 Fe0:05 Ti0:01 )§=2:00(Si2:99 Al0:01 )§=3:00 O12 : (2) Fe3 Al2 (SiO4 )3 :Polymorphism & Series:
Mineral Group:Forms two series, with pyrope, and with spessartine.

Garnet group.

Occurrence: The most common garnet, typically in mica schists and gneisses, from regionallymetamorphosed argillaceous sediments and pelites; also in contact metamorphic hornfels. Ingranites and eclogites; in sedimentary rocks; as a detrital mineral.
Association: Biotite, cordierite, chlorite, staurolite, andalusite, kyanite, sillimanite, hematite,plagioclase, amphibole, pyroxene.
Distribution: Widespread. Some localities for ¯ne crystals include: in the Zillertal, Tirol,Austria. At Falun, Sweden. In Norway, from near Bod¿. From the Akhmatovsk deposit, near
Zlatoust, Ural Mountains, Russia. In the USA, from Roxbury, Litch¯eld Co., and Southbury,
New Haven Co., Connecticut; at Auburn, Androscoggin Co., and Topsham, Sagadahoc Co.,
Maine; from West¯eld and Russell, Hampden Co., Massachusetts; and at Hanover, Grafton Co.,
New Hampshire. From Avondale, Chester Co., Pennsylvania; a large commercial deposit at theBarton mine, North Creek, Warren Co., New York; at Michigamme, Marquette Co., Michigan;from Salida, Cha®ee Co., Colorado; and at Ft. Wrangell, Stikine River, Alaska. In Brazil, at
Pernambuco, Bahia. From the Miami district, Zimbabwe. At Broken Hill and Thackaringa, NewSouth Wales, and in the Harts Range, Northern Territory, Australia. From Yamanoo, Ibaragi
Prefecture, and the Ishikawa district, Fukushima Prefecture, Japan.
Name:For Alabanda in Turkey, a cutting center in antiquity.

References: (1) Dana, E.S. (1892) Dana's system of mineralogy, (6th edition), 437{447.
(2) Deer, W.A., R.A. Howie, and J. Zussman (1982) Rock-forming minerals, (2nd edition),v. 1A, orthosilicates, 468{698, esp. 537{589. (3) Novak, G.A. and G.V Gibbs (1971) The crystal
chemistry of the silicate garnets. Amer. Mineral., 56, 791{825.
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