AM_Topaz_18 Formula: Al2 Si O4 F2 Name: Topaz Unit cell: 4.5841 8.7308 8.2316 90.0 90.0 90.0 , V=329.45 Space group: PBNM (62)

Gatta G D , Nestola F , Ballaran T B , Physics and Chemistry of Minerals , 33 (2006) p.235-242, Elastic behaviour and structural evolution, of topaz at high pressure, Locality: Ouro Preto, Minas Gerias, Brazil, Sample: P = 8.39 GPa