Kyanite Al2SiO5 Triclinic
Sillimanite Al2SiO5 Orthorhombic
Andalusite Al2SiO5 Orthorhombic
Aluminum Silicate polymorphs
Phase diagrams
structural considerations of als occurrences
map of als occurrences in new england
tectonic reconstructions of new england
influence of heat flow and tectonic setting on als occurrence
Other Nesosilicates of Particular Importance
Chloritoid (Fe,Mg)2Al4O2(SiO4)2(OH)4 Monoclinic
- alternating brucite-like and corundum-like octahedral layers that are
bridged by isolated SiO4 tetrahedra
Staurolite Fe2Al9O6(SiO4)4(O,OH)2 Monoclinic
- monoclinic, commonly as pseudo-orthorhombic, twinned crystals. Medium
to high grade metamorphic rocks. - kyanite-like portions of unit cell
Titanite ('Sphene') CaTiSiO5 Monoclinic
- common Ti-bearing accessory. Monoclinic, commonly in wedge shapped crystals.
Topaz Al2SiO4(F,OH)2 Orthorhombic
Zircon ZrSiO4 Isometric