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Phosphate

Mantienneite

KMg₂Al₂Ti(PO₄)₄(OH)₃·15H₂O
Hardness2–3
Crystal systemOrthorhombic
ClassPhosphate
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Mantienneite specimen

Mantienneite, is an extremely rare K-Mg-Al-Ti phosphate found only in 3 localities worldwide, it's present here as a lot of about 1 mm brown granules in a capsule. Some of the granules have microcrystals of the mineral. From: Anloua, Martap, Vina, Adamaoua Region, Cameroon. — Photo: David Hospital · CC BY-SA 4.0

Mantienneite

Mantienneite is an IMA-recognized mineral species in the phosphate class, with the chemical formula KMg₂Al₂Ti(PO₄)₄(OH)₃·15H₂O.

It crystallizes in the orthorhombic crystal system (space group Pbca).

Key properties: Mohs hardness 2–3; specific gravity 2.31; Pale brown with a rose tint streak; Vitreous luster; optically biaxial.

IMA symbol Mtin, IMA status: approved, named in 1983.

Replacing minerals in and forming the matrix of sandy layers in lacustrine shale.

It is found associated with Kaolinite, siderite, quartz, vivianite, organic matter.

The mineral was named to honor Dr. Joseph Mantienne (1929–), Bureau de Recherches Géologiques et Minières, Orlèans, France.

Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet. Browse more M minerals or help write this entry.