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Piemontite-(Sr)

Year of discovery: 1990 (Cassagna mine, Italy, and Molinello mine, Italy), 1986 (Japan)

Locality list: 9 localities of piemontite-(Sr)

• CaSrMnAl₂(SiO₄)₃(OH)
• [Ca²⁺][Sr²⁺][Mn³⁺][Al³⁺₂][OH|O|SiO₄|Si₂O₇]^13-

• Class: Epidote group < Epidote supergroup
• Class: Sorosilicate - Nesosilicate - Oxide - Hydroxide

• Sr => Ca: Piemontite
• Sr => Pb: Piemontite-(Pb)

• Mn => Al: Clinozoisite-(Sr)
• Mn => Fe: Epidote-(Sr)

• Al => Mn: Manganipiemontite-(Sr)

• Color: Dark red
• Streak: Purplish brown
• Luster: Vitreous
• Diaphaneity: Transparent

• Cleavage: Perfect on {001} (1 plane)
• Hardness: 6
• Density: 3.7

• System: Monoclinic
• Group: 2/m, P2₁/m
• Lattice: a=8.9, b=5.7, c=10.2, β=114.7

Synonym: Strontiopiemontite