Amaterasuite

amaterasuite

matsubaraite

rutile

titanite

Images

Formula: Sr₄Ti₆Si₄O₂₃(OH)Cl
Valence: Sr₄Ti⁴⁺₆Si₄O₂₃(OH)Cl
Cyclosilicate, ring silicate, strontium- and titanium- bearing mineral
Crystal system: Orthorhombic
Specific gravity: 4.0 calculated
Hardness: 6
Streak: White
Colour: Deep blue to green
Luminescence: Not fluorescent under UV
Environments

Metamorphic environments

Amaterasuite is a new mineral, approved in 2024 and to date (January 2026) reported only from the type locality.

Localities

At the type locality, the amaterasuite type locality, Mt Ohsa, Niimi City, Okayama Prefecture, Japan, amaterasuite was discovered in jadeitite outcrops. These outcrops have produced other new and extremely rare strontium (-titanium) silicates, including itoigawaite, rengeite and matsubaraite. Matsubaraite is closely associated with amaterasuite and shares compositional and structural elements with it. Both minerals occur in close association with rutile and are spatially associated with rims in titanite formed from the breakdown of rutile (AM 111.167–171).
The amaterasuite occurs as of needle– to plate– shaped crystals as large as 150 µm around rutile (Mindat).
Amaterasuite from Mt Ogsa - Image

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