Next Seminar: Monday, October 14, 2019 7:00 PM

Color in Minerals and Why it is Important

Terry Smith, Ph.D., 3M Technical Director of Corporate Research, Retired

LOCATION: University of Minnesota East Bank campus

Vincent Hall, 206 Church St. SE, Minnesota MN 55455 Room 16. MAP

Summary:

The color of minerals has been a source of scientific and culture fascination since antiquity. The color is responsible for much of the lore and mystique of minerals. However, it has only been in the last century, with the development of quantum mechanics that we can finally understand the origin of the color centers in minerals. A rudimentary understanding of several theories is required to understand the diverse mechanisms for coloration. Crystal Field Theory provides insight into color center localized on a specific atom, Molecular Orbital Theory is required to explain color centers on groups of atoms, Band Gap Theory is required to explain colors involving large ensembles of atoms. Another cause of color is various optical effects caused by scattering, diffraction and refraction of light which explains phenomena such as opalescence and iridescence. Interestingly, although a lot is known about the various color centers, there is still controversy and ambiguity around the exact details of many color centers, even in common gem stones. Much of this confusion is due to the fact that the color is often the result of small levels of impurities or defects that are difficult to identify. (It is ironic that many of the most valued gems are the result of these imperfections.) The birthstones will be used to exemplify how these diverse theories help explain colors in minerals. Some of the fascinating lore and history about minerals will also be explored.

Biography:

Dr. Terrance (Terry) Smith worked in industry for over 34 years. His entire career was spent at 3M, and a 3M Spin-off, Imation Corporation. He began his industrial career at 3M in the Graphic Research Laboratory, developing new dyes and colorants for the emerging digital imaging markets. He was also involved in developing new organic semiconductors, semiconductor devices, and processes for making inexpensive flexible electronics. His work resulted in over 20 publications and over 35 U.S. issued patents. Terry retired from 3M as the Technical Director of the 3M Corporate Research Materials Laboratory (CRML). Most of the latter part of Terry’s career was spent managing the development of new materials and processes for industrial, healthcare and electronics markets. 

Terry Smith received his B.S. in Chemistry from the University of Minnesota in 1977 and his Ph.D. from the California Institute of Technology in 1982 (Advisor: Professor Harry Gray). He also spent 2 years as a post-doctoral affiliate at Stanford University (Advisor: Professor Henry Taube). He continues to serve on various advisory boards at MIT and the University of Minnesota.

Terry’s hobby include travel, zymurgy (beer making), collecting minerals (mostly on the internet!), studying mineralogy, and hiking.