Sonolite

Sonolite
Sonolite (in bottom left corner) with zincite and manganosite
General
CategorySilicate minerals
FormulaMn9(SiO4)4(OH,F)2
IMA symbolSnl
Strunz classification9.AF.55
Dana classification52.3.2d.3
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupP21/b
Unit cella = 4.87 Å, b = 10.66 Å
c = 14.28 Å
β = 100.3°, Z = 2
Identification
ColorRed-orange, pinkish brown to dark brown
Colorless in thin section
TwinningCommon, singular or lamellar on {101}
Mohs scale hardness5.5
LusterVitreous, dull
DiaphaneityTransparent to translucent
Density3.82–4.00 (measured)
Optical propertiesBiaxial (−)
Refractive indexnα = 1.765
nβ = 1.778
nγ = 1.787
Birefringenceδ = 0.022
2V angle75° to 82° (measured)
Dispersionr > v
References

Sonolite is a mineral with formula Mn9(SiO4)4(OH,F)2. The mineral was discovered in 1960 in the Sono mine in Kyoto Prefecture, Japan. In 1963, it was identified as a new mineral and named after the Sono mine.