Manganese Minerals in Clays: A Review

F. V. Chukhrov, A. I. Gorshkov, E. S. Rudnitskaya, V. V. Beresovskaya and A. V. Sivtsov
Institute of Ore Geology, Petrography, Mineralogy, and Geochemistry Academy of Sciences, Moscow 17, U.S.S.R.

Abstract: Vernadite (MnO2 · nH2O) is a mineral with a poorly ordered structure. Its synthetic analogue is designated δ-MnO2. Birnessite and vernadite are independent mineral species and cannot be described further under the same name. They have similar hexagonal unit-cell parameters, a0, but different c0 parameters. Rancieite has a structure similar to that of birnessite. Calcium bearing, 14-Å birnessite occurring in nature was first described by the authors. In addition to the todorokite having the parameters a0 = 9.75 Å, b0 = 2.84 Å, and c0 = 9.59 Å, other species of natural todorokite are known having a0 parameters that are multiples of 4.88 Å equal to 14.6 and 24.40 Å, the b0 and c0 parameters being the same.

Key Words: Birnessite • Ca-birnessite • Manganese • Rancieite • Todorokite • Vernadite

Clays and Clay Minerals; October 1980 v. 28; no. 5; p. 346-354; DOI: 10.1346/CCMN.1980.0280504
© 1980, The Clay Minerals Society
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