Chlorite

Crystal System: Monoclinic
Status of Occurrence: Confirmed Occurrence
Distribution: Widespread
Chemical Composition: variable (depending on individual species) magnesium, iron, manganese, lithium and nickel aluminium silicate hydroxide
Chemical Formula: A5-6Z4O10(OH)8 where A = Al, Fe2+, Fe3+, Li, Mg, Mn, Ni (or a combination of two or more of these elements) and Z = Al, Si, Fe3+ (or a combination)
Method(s) of Verification: see individual entries for chamosite, clinochlore, cookeite and pennantite for details.

Chemical Group:

  • Silicates

Geological Context:

  • Hydrothermal
  • Metamorphic: low-grade
Chlorite, forming by the alteration of biotite, showing blue interference colours. Viewed under the microscope in plane polarized light. Specimen National Museum of Wales (NMW 93.12G), © National Museum of Wales.
Introduction: chlorite covers a relatively large and common group of minerals, although not all of its members are well known. The term chlorite is used to denote any member of this group when differentiation between the different members is not possible. These minerals are most commonly found in low-grade metamorphic rocks with, in many instances, the composition of the chlorite mineral being influenced by the composition of the rock in which it occurs. See individual entries for chamosite, clinochlore, cookeite and pennantite.
Occurrence in Wales:

Key Localities:

There are no key localities for this specimen.

References:

There are no references for this specimen.