A commercial product composed of silicon carbide that is used as an abrasive in cutting, grinding and polishing applications. Carborundum® is a registered trademark of The Carborundum Corporation.

Carlosturanite is a rare antigorite-like mineral that apparently contains vacant tetrahedral sites which interrupt the continuity of the tetrahedral sheet without affecting the continuity of the octahedral sheet (Mellini et al., 1985). The structure is thus similar to a modulated serpentine. To maintain charge balance, OH groups substitute for O atoms. The generalized formula is M₂₁[T₁₂O₂₈(OH)₄](OH)₃₀. H₂O, where M = Mg, Fe³⁺, Mn²⁺, Ti⁴⁺, and Cr³⁺, and T = Si, Al. Alberico (1998) showed that there are problems with the model of Mellini et al. (1985), and suggested the need to reexamine the structure. Important occurrences are related to low grade metamorphic (serpentinite) environments.
Cf., antigorite

See hydrotalcite group.

Solid fine to very fine-grained substances, e.g. clay minerals, with the following properties: 1. negligible dissolution within the active material, 2. able to bind the active substance by sorption, and 3. capable of releasing the active material under specific conditions. Smectite, talc, and other clay minerals are used as a drug carrier or a carrier for pesticides.

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.

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.

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