Humite (mineral group)

{{for|the specific mineral|Humite}}

The humite groupGaines et al (1997) Dana's New Mineralogy Eighth Edition, Wiley is a group of nesosilicates with the general formula {{chem2|A_{n}(SiO4)_{m}(F,OH)2}}.

When A is predominantly magnesium we have the humite subgroup:

• norbergite, {{chem2|Mg3(SiO4)(F,OH)2}}
• chondrodite, {{chem2|(Mg,Fe,Ti)5(SiO4)2(F,OH,O)2}}
• humite, {{chem2|(Mg,Fe)7(SiO4)3(F,OH)2}}
• clinohumite, {{chem2|(Mg,Fe)9(SiO4)4(F,OH)2}}

The manganese-humite subgroup has members

• alleghanyite, {{chem2|(Mn(2+))5(SiO4)2(OH,F)2}}
• manganhumite, {{chem2|(Mn,Mg)7(SiO4)3(OH)2}}
• sonolite, {{chem2|Mn9(SiO4)4(F,OH)2}}

and the leucophoenicite subgroup has members

• ribbeite, {{chem2|Mn5(SiO4)2(OH)2}}
• leucophoenicite, {{chem2|(Mn,Ca,Mg,Zn)(SiO4)3(OH)2}}
• jerrygibbsite {{chem2|(Mn,Zn)9(SiO4)4(OH)2}}

Chondrodite is the most common member of the humite group. It may contain Ti up to 9.6% {{chem2|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.Phillips, W R and Griffen, D T (1981) Optical Mineralogy, pages 142 to 144