Manganocummingtonite

Formula:  []Mn₂(Mg,Fe)₅Si₈O₂₂(OH)₂

Origin of name:  From manganese and cummingtonite

Crystal system:  Monoclinic

Crystal class:  2/m

Twinning: 

Unit cell: 

Colour:  Pale greenish white, light green, pink to rose-red, tan, pinkish-red

Diaphaneity:  Transparent to translucent

Luster:  Vitreous

Habit:  Crystals long prismatic to acicular, twinning common, in compact aggregates

Hardness:  6 to 6.5

Specific gravity:  3.07 to 3.13   

Cleavage:  3; {110} perfect, {100} imperfect, {001} parting

Tenacity: 

Streak: 

Synonyms/varieties:

Comments:  Series with manganogrunerite and with cummingtonite