Mineralpedia Details for Manganoneptunite
Named for the abundance of manganese and as a chemical variant of the neptunite structure. Manganoneptunite is a rare mineral that occurs in only a few countries worldwide including in Russia, the United States, Canada, Malawi, Morocco and Namibia. It is found as a late-forming segregation mineral in nearly all rock types at its Russian localities in the Lovozero massif in Russia.
Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/manganneptunite.pdf
Manganoneptunite from Poudrette quarry, Mont Saint-Hilaire, Montérégie, Québec, Canada
Deep red, root beer red, much like red sphalerite with a vireous luster, well-formed monoclinic prisms to 4mm.