A modulated layer silicate based on the serpentine structure, with an approximate ideal composition of Mn²⁺₃Si₂O₅(OH)₄. Fe, Mg, and Al can substitute for Mn. There is an apparent excess of Si and an apparent deficiency in octahedral composition on the basis of oxygen atoms. Earlier literature sometimes described caryopilite as bementite, but it has been shown that they are separate species. A monoclinic polytype is dominant and small amounts of a trigonal phase are often intergrown. Caryopilite, like greenalite, is an “island” structure where Si-rich tetrahedra of a given layer have apical oxygen atoms coordinate to one octahedral sheet and others to the adjacent sheet (Guggenheim and Eggleton, 1998). The islands are saucer- shaped with some islands inverted, and the islands are domed. Island diameters depend on composition with larger-diameter islands having smaller average octahedral cation sizes (4 tetrahedral-ring diameters in greenalite, 3 rings in caryopilite). Island domains are randomly displaced within layers. “Baumite”, a mixture of several phases, contains a phase, probably Zn,Mg-rich, that is intermediate in domain structure to greenalite and caryopilite. Caryopilite is commonly found in bedded manganese deposits, such as those at the North Chichibu belt in the Shikoku region, SW Japan.
Cf., greenalite

A poorly defined material, possibly mica and manganoan andradite.

An obsolete term for muscovite.

An obsolete term for muscovite.

See catalyst.

A catalyst is a substance that influences the rate of a chemical reaction without being consumed by the reaction. Catalysis is the process by which a catalyst influences a reaction, and this process often involves adsorption or the formation of intermediate compounds. When catalysis occurs, the overall Gibbs free energy of the reaction does not change.

See poultice.

A poorly defined material, possibly alteration product with dominant muscovite.

An obsolete term for a chocolate-brown saponite-rich material from Cathkin Hills, Scotland.

See electrode.