AM_Topaz Formula: Al2 Si O6 H2 Name: Topaz Unit cell: 4.7238 8.9473 8.39 90.0 90.0 90.0 , V=354.61 Space group: PBNM (62)

Wunder B , Rubie D C , Ross C R , Medenbach O , Seifert F , Schreyer W , American Mineralogist , 78 (1993) p.285-297, Synthesis, stability, and properties of Al2SiO4(OH)2: A fully hydrated, analogue of topaz