Vernadite, MnO2 . H2O, is poorly crystalline and not well studied (Post, 1999). It is a mixture of nano-plates of birnessite, buserite, and interstratified birnessite / buserite. Vernadite occurs in the oxidized zone of Mn ore deposits, as buried manganese nodules on the sea floor, and ferromanganese crusts on seamounts. In soils (Chukhrov et al., 1980), vernadite is believed to be related to microbial oxidation of Mn2+.
An obsolete term for celadonite.
An obsolete term for celadonite.
A method of measuring intramolecular or intracrystalline modes of motion (vibrational modes) by observing the interaction of incident radiation with a sample. Common techniques used to obtain spectra are infrared and Raman spectroscopy, and inelastic neutron scattering.
Cf., spectroscopy, normal mode
The measured hardness of a surface as tested using a special diamond pyramid-shaped indenter under various loads. A Vickers number is reported based on surface area indented (in mm2) divided by pressure (in Newtons).
Cf., hardness, Mohs hardness
A general term used in the pelotherapy clay industry to denote an unmodified (“raw”) clay from a deposit, before maturation with saline or mineral water.
An obsolete term for an iron-rich chlorite.
A measure of the resistance of a fluid to flow when the fluid is placed under stress.
An obsolete term for a mixture of allophane and wavellite from Santa Rosa de Viterbo, Colombia.
Glassy luster.
Cf., luster