Formula: Mn2+9(SiO4)4(OH)2
Nesosilicate (insular SiO4 groups), humite group, forms a discontinuous solid solution with clinohumite (Dana)
Specific gravity: 3.82
Hardness: 5½
Streak: Pale reddish-orange (Dana)
Colour: Red-orange, pinkish brown to dark brown
Solubility: Gelatinises with acids (Dana)
Common impurities: Ti,Al,Fe,Mg,Ca,H2O,C

Metamorphic environments

Sonolite occurs in metamorphosed manganese-rich skarn deposits associated with other manganese minerals, including rhodonite, spessartine, rhodochrosite, tephroite, braunite and jacobsite. It also occurs in manganese chert (Dana).

At the type locality, the Sono mine, Wazuka-cho, Soraku District, Kyoto, Japan, sonolite is associated with rhodochrosite, galaxite and pyrochroite (Lauf p54, HOM).

At the Malocidelnikovskoye deposit, Yekaterinburg region, Ural mountains, Russia, sonolite occurs with rhodochrosite, rhodonite and other manganese minerals (Dana)

At Franklin, New Jersey, USA, sonolite is much more abundant than alleghanyite or leucophoenicite. It forms in franklinite - willemite - zincite ore, often associated with manganosite and zincite (Lauf p54). The samples are characterized by primary, relatively simple assemblages of several species which may include manganosite, willemite, sonolite, hetaerolite - franklinite exsolution intergrowths, jerrygibbsite, leucophoenicite, zincite (usually with abundant hetaerolite exsolution), and a relative scarcity of carbonates (AM 70.382-384).

At Sterling Hill, New Jersey, USA, sonolite crystals form on calcite - rich franklinite/willemite ore with no associated zincite. Sonolite also occurs as reaction rims on zinc-rich tephroite which has abundant willemite exsolution. The associated minerals are zincite, franklinite, willemite and calcite (AM 70.382-384).

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