Manganoneptunite

minerals

villiaumite

lorenzenite

lomonosovite

Formula: KNa2LiMn2+2Ti2Si8O24
Inosilicate (chain silicate), neptunite group, and forms a series with it
Specific gravity: 3.23
Hardness: 5 to 6
Streak: Red-brown
Colour: Red
Solubility: Insoluble in acids
Environments:

Plutonic igneous environments
Pegmatites

Manganoneptunite is found as a late segregation mineral in almost all rock types, including syenite and syenite pegmatites (Webmin. HOM).

Localities

At Saint-Amable, Canada, manganoneptunite occurs in miarolitic cavities in a nepheline syenite sill (HOM).

At the type locality, Maly Mannepakhk Mountain, Khibiny Massif, Murmansk Oblast, Russia, manganoneptunite was found locally in the contact zone of the massif, associated with fibrous aegirine, natrolite, analcime, lamprophyllite, murmanite, lomonosovite, eudialyte, pectolite, villiaumite and sodalite (AM11.289-299, HOM), and also with lorenzenite (AM 12.96-97 )

At Point of Rocks, Colfax county, New Mexico, USA, manganoneptunite occurs in syenite and syenite pegmatite (Dana).

Back to Minerals