A discredited name, now known to be a Mn-rich chlorite, pennantite.

An obsolete term for illite.

An obsolete term for poorly described Ni- and Mg-rich phyllosilicates, generally characterized as “garnierite”.

The Mn-analogue of cronstedtite, a serpentine. Guidottiite has an ideal composition of (Mn₂Fe³⁺)(SiFe³⁺)O₅(OH)₄. Guidottiite-2H₁ and -2H₂ were reported by Wahle et al. (2010) with random interstratified polytype intergrowths and stacking disorder common. The sample comes from the Kalahari Manganese field, South Africa, and forms from hydrothermal solutions.

An obsolete term for illite-2M₂.

See “deweylite”.

See reyerite group.