AM_Mattheddleite
Formula: Pb5 (Si1.5 S1.5) O12.43 (Cl.57 H.43)
Name: Mattheddleite
Unit cell: 10.0056 10.0056 7.496 90.0 90.0 120.0 , V=649.90
Space group: P63/M (176)

Steele I M , Pluth J J , Livingstone A , Mineralogical Magazine , 64 (2000) p.915-921, Crystal structure of mattheddleite: a Pb, S, Si phase with the apatite structure, Locality: Leadhills, Scotland