For the specific mineral, see
Humite .
The humite group [ 1] is a group of nesosilicates with the general formula An (SiO4 )m (F,OH)2 .
When A is predominantly magnesium we have the humite subgroup:
norbergite , Mg3 (SiO4 )(F,OH)2
chondrodite , (Mg,Fe,Ti)5 (SiO4 )2 (F,OH,O)2
humite , (Mg,Fe)7 (SiO4 )3 (F,OH)2
clinohumite , (Mg,Fe)9 (SiO4 )4 (F,OH)2
The manganese -humite subgroup has members
and the leucophoenicite subgroup has members
Chondrodite is the most common member of the humite group. It may contain Ti up to 9.6% TiO2 . Chondrodite from Sterling Hill Mine and Franklin Mine contains zinc to 11.5% ZnO and Mn to 36% MnO, and grades to alleghanyite.
The humite minerals commonly alter to serpentine or Mg-rich chlorite and dissolve by weathering , leaving iron oxide residues.[ 2]
References
^ Gaines et al (1997) Dana's New Mineralogy Eighth Edition, Wiley
^ Phillips, W R and Griffen, D T (1981) Optical Mineralogy, pages 142 to 144