The Mineralogical Society


Southern California

967th Meeting

 April 12, 2019

Program: Petroglyphs, Dendrites and Manganese Oxide Minerals

Presented by Dr. George Rossman

April 12, 2019 at 7:30 PM

Pasadena City College
Building E, Lecture Hall (room 220)
1570 E. Colorado Boulevard
Pasadena, California

About us…

The Mineralogical Society of Southern California is dedicated to the dissemination of a general knowledge of the mineralogical and related earth sciences through the study and collecting of mineral specimens. Organized in 1931, it is the oldest mineralogical society in the western United States.
The MSSC is a scientific non-profit organization that actively supports the Pasadena City College Geology Department, its associated Dana Club,, and the Field Science Scholarship Fund. Support is also given to the San Bernardino County Museum of Natural History and Mindat.
The MSSC is affiliated with the California Federation of Mineralogical Societies and American Federation of Mineralogical Societies.

About the Program: Petroglyphs, Dendrites and Manganese Oxide Minerals.  Presented by Dr. George Rossman

Purely manganese oxides include hausmannite, manganosite, pyrolusite and ramsdellite.  Other manganese oxides, many with a chemical formula close to MnO2, contain ‘foreign’ ions within open spaces in their structures. They include birnessite, coronadite, crytomelane, hollandite, manjiroite, nsutite, ranceite, romanechite, todorokite, and vernadite. Some of these phases are common components of manganese dendrites, but the so-called “pyrolusite” dendrites have never been shown to contain pyrolusite. Manganese oxide is also an important constituent of desert varnish which is the rock coating that is broken through to show the lighter rock beneath in petroglyphs. Our talk will discuss such occurrences of manganese oxides and what we have to do to identify the manganese oxide species in the laboratory.

MSSC President, George R. Rossman is an American mineralogist and the Professor of Mineralogy  at the California Institute of Technology. His research Interests include: Mineralogy. The relationship between the spectroscopic properties of minerals and mineral composition and structure

Upcoming Events

  • May 10: The Webers- Rainforest Jasper of Queensland Australia
  • June 14, 2019: Bruce Carter – Mineralogical – Santa Cruz Island
  • July 12, 2019: Peter Goetz: Slovakian Opal
  • August, 2019: MSSC Annual Picnic
  • June 9, 2019: MSSC Board meeting at Bruce Carter’s House
  • Field Trip April 13, 2019: Mule Canyon Rd in Calico Mountains
  • Field Trips, click here to go to field trip page

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