Manganese minerals in geodes from Chihuahua, Mexico
- 1 March 1974
- journal article
- research article
- Published by Mineralogical Society in Mineralogical Magazine
- Vol. 39 (305) , 549-558
- https://doi.org/10.1180/minmag.1974.039.305.07
Abstract
Summary: Seven manganese minerals have been observed in geodes from Chihuahua, Mexico. Ramsdellite occurs in a number of different habits, but the morphology and precession X-ray patterns suggest that it is pseudomorphous after groutite. Pyrolusite is found only in association with rams-dellite and is believed to be an alteration product of that mineral. Todorokite generally occurs as a late-stage fibrous overgrowth in many of the geodes. Ranciéite, birnessite, hollandite, and cryptomelane are present in trace amounts. This assemblage of manganese minerals is typical of supergene mineralization.This publication has 3 references indexed in Scilit:
- The mineralogy of manganese nodules from a range of marine environmentsMarine Geology, 1972
- The Crystal Structure of Ramsdellite, an Orthorhombic Modification of MnO2.Acta Chemica Scandinavica, 1949
- The manganese oxide minerals, a preliminary reportEconomic Geology, 1943