Morinite

minerals

montebrasite

augelite

wavellite

Formula: NaCa2Al2(PO4)2(OH)F4.2H2O
Hydrated phosphate containing halogen
Specific gravity: 2.94
Hardness: 4 to 4½
Streak: White
Colour: Colourless, white, light rose-pink; colourless to light rose-pink in transmitted light.
Solubility: Decomposed by hot sulphuric acid and incompletely so in cold sulphuric acid or aqua regia (Mindat)
Morinite inverts irreversibly to an apatite structure at about 400oC, and to a whitlockite structure if heated in thin films in air to about 800oC (AM 45.645-667).
Environments:

Pegmatites

Morinite is an uncommon late-stage mineral in complex granite pegmatites, associated with montebrasite, apatite, augelite, wardite, wavellite and cassiterite (HOM).

At Tom's quarry, Kapunda, Mount Lofty Ranges, South Australia, morinite occurs in two different associations. Firstly in cavities associated with leucophosphite, cacoxenite, meurigite-Na and variscite, often perched on needles of wavellite. Secondly, morinite occurs in the xanthoxenite - ushkovite assemblage, perched on fluorapatite (AJM 17.1.23).

At the type locality, the Montebras Mines, Creuse, Nouvelle-Aquitaine, France, morinite occurs in granite associated with wavellite, wardite, roscherite, cassiterite and apatite (Mindat).

At the Hugo mine, Keystone, South Dakota, USA, morinite is associated with montebrasite, apatite, augelite, wardite, crandallite, quartz and clay (Dana, AM 43.585-594).

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