AM_Piemontite_12 Formula: Ca2 (Al1.74 Mn1.26) Si3 O13 H Name: Piemontite Unit cell: 8.8625 5.7006 10.1822 90.0 115.525 90.0 , V=464.21 Space group: P121/M1 (11)

Nagashima M , Akasaka M , American Mineralogist , 89 (2004) p.1119-1129, An X-ray Rietveld study of piemontite on the join, Ca2Al3Si3O12(OH) - Ca2Mn3+3Si3O12(OH) formed by hydrothermal synthesis, Sample: q = 1.5, p = 1.25, Synthesis at P=350 MPa, T=500 C