Keweenaw Mineral Days: A Presentation by Dr. John Rakovan

Presentation Title

New insights into the Structure and Formation of Wire Silver and Gold

Date

Monday, August 3 at 7pm

Location

the Alumni Center (formerly the Advanced Technology Development Complex)

Speaker's Biography:

Dr. John Rakovan is the state mineralogist and director of the New Mexico Mineral Museum at the New Mexico Bureau of Geology and Mineral Resources. He has been an executive editor of and regular contributor to Rocks & Minerals magazine since 2001 and was a professor of mineralogy at Miami University for 25 years.  John has broad research interests including crystal growth, structural and morphologic crystallography, and mineral deposit formation. He has been a mineral collector for more than 50 years and focuses on minerals that are involved in his research pursuits including apatite and layer silicates.

Presentation Description:

Much more common in silver than in gold, the unusual morphology known as a “wire” can resemble the finest of threads to the strongest of ropes.  Although they have adorned the shelves of mineral collections for centuries, very little has been known about wire specimens until recently.  Are they single crystals or bundles of many fibrous crystals? How do they grow? Some have suggested extrusion. Answers to these questions and the discovery of unexpected and yet unexplained isotope fractionation have resulted from our work.  The study has included some of the finest known examples of wire silver and gold and has utilized some of the world’s most powerful scientific instruments including the neutron diffraction and spectroscopy facilities at Los Alamos National Laboratory. Although preliminary, some results on wire copper, including specimens from the Keweenaw Peninsula will be discussed.