Neotocite

neotocite

spessartine

hisingerite

rhodonite

Images

Formula: (Mn,Fe)SiO3.H2O(?) phyllosilicate (sheet silicate)
Forms a series with hisingerite

Varieties

Chinglusuite is a variety of neotocite

Properties

Specific gravity: 2.43
Hardness: 3 to 4
Streak: Brown
Colour: Black, dark brown to dark olive-green, dark red-brown
Solubility: Decomposed by hydrochloric acid (Dana)
Common impurities: Al,Mg,Ca,Na,K,C
Environments:

Pegmatites
Hydrothermal environments

Neotocite is a secondary mineral formed from the alteration of rhodonite and other manganese silicates, associated with rhodonite, calcite and quartz. It is frequently found as veins in weathered manganese-bearing pyroxenes, especially rhodonite, and also in spessartine. It is also found lining fractures in granite pegmatites (Dana).

At the Chinglusuai River Valley, Lovozersky District, Murmansk Oblast, Russia, neotocite variety chinglusuite has been found on feldspar (FM 41230).

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