Gedrite Magnesiogedrite , Comments: Dark gray cleavage fragment of magnesiogedrite (gedrite). , Location: Bamble, Telemark, Norway. , Scale: See Image.
Good on {100}
(Mg,Fe2+ ) 2[(Mg,Fe2+ ) 3Al 2](Si 6Al 2)O 22(OH) 2Anthony et al , Handbook of mineralogy (2001)
(Ca,Fe,Mn,Mg) 3Al 2BSi 4O 15(OH)Walter Schumann , Gemstones of the world (2001) More from other references