University of Colorado

Mineral Structure Data

Aluminosilicate Group

The aluminosilicate group is composed of minerals of the general formula Al2SiO5

The crystal structure of sillimanite.


The crystal structure of andalusite


The crystal structure of kyanite


The crystal structure of topaz


                Sillimanite Andalusite  Kyanite     Topaz
                Al2SiO5      Al2SiO5      Al2SiO5     Al2SiO4(F,OH)2                    

Form.Wt. 162.05 162.05 162.05 182.0 Z 4 4 4 4 CrystalSystem Orth Orth Tric Orth PointGroup mmm mmm -1 mmm SpaceGroup Pbnm Pnnm P-1 Pbnm UnitCell a(Å) 7.4883 7.7980 7.1262 4.6651 b(Å) 7.6808 7.9031 7.8520 8.8381 c(Å) 5.7774 5.5566 5.5747 8.3984 alpha 89.99 beta 101.11 gamma 106.03 Vol(Å3) 332.29 342.44 293.72 346.27 MolarVol 50.035 51.564 44.227 52.140 Density 3.2386 3.1426 3.6640 3.492 Thermal Expansion(Volumetric) alpha 13.3 22.8 25.1 14.8 a0 0.1260 0.2181 0.2505 0.1098 a1 0.2314 0.3261 0.0 1.2700 a2 0.0 0.0 0.0 0.0 Elastic Properties Ks(GPa) 170.8 162. 193. 167.4 G(Gpa) 91.5 99.1 114.8

Mineral Data Base Index

GEOL 1010 Syllabus

GEOL 3010 Syllabus

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