Mineral Symposium 2023: Mineral Evolution

Saturday, March 18, 2023
9 AM - 4:30 PM

Prepaid reservations are required. Cost includes all presentations, breakfast and lunch, as well as Museum admission. Registration ends Wednesday, March 15, 2023 at 5 PM.

From the dozens of minerals that formed during the earliest days of our solar system, the count of minerals now includes 5,780 and continues to grow. Come explore how the formation of planets, geologic processes, and interactions with air, water, and even life have diversified the mineral inventory. Through the lens of mineral evolution, speakers will show how minerals clue us in to the processes that formed them.

Speaker lineup to be announced at a later date.


Formation and Recognition of Subduction Zone Mineral and Rock Assemblages

Tom Weiland, Ph.D.
Professor Emeritus, Department of Chemistry, Geology, & Physics, Georgia Southwestern State University

Tom received a bachelor’s degree in Geology from East Carolina University and later earned a M.S. and Ph.D. at UNC-Chapel Hill with a focus on Caribbean volcanism and igneous petrology.  He then worked for thirty years as a geology professor at Georgia Southwestern State University.  During this time he taught a range of geology courses including mineralogy, optical mineralogy, igneous and metamorphic petrology and field methods.  He also led several international studies courses in Central and South America that focused on service learning and natural history.  Throughout his career Tom worked part-time as a consultant for the clay mining industry with a focus on atomic structure of clays and the mineral phases they form when subjected to high temperatures.  He also partnered with Georgia K-12 science teachers in the design, development and distribution of rock, mineral and fossil kits that are now used in many classrooms throughout the state.  Tom has recently retired and is an Emeritus Professor.

Subduction zone dynamics and the igneous and metamorphic processes that define these tectonic boundaries have temporal and spatial characteristics relative to pressure, temperature and chemical conditions. In addition to an overview of magma production, melt crystallization and regional metamorphism in these areas, Thomas will discuss mineral polymorphs and assemblages that are commonly used to recognize and describe both modern-day and relict (ancient) subduction zones. There will be a focus on mineral formation and stability in these highly variable environments. Volcanic and metamorphic rock terrains from Costa Rica, Puerto Rico and Georgia will be used to showcase active and relict subduction zone deposits.

The History of a Pegmatite in a Gemstone

Raquel Alonso Perez, Ph.D.
Curatrix, Mineralogical and Geological Museum, Harvard University

Dr. Alonso-Perez received her B.S. in geology from the University of Granada, Spain, and her Ph.D. in Earth and Material Sciences from the Swiss Federal Institute of Technology (ETH) in Zurich, Switzerland, and graduated as gemologist by the Gemological Association of Great Britain (GEM-A). Her research interests are evolved from understanding Earth forming processes to the origin of gem deposits by using a dual approach of non-destructive analytical techniques. As Curatrix of the MGMH Raquel is responsible for access to, teaching, research, public education, and continued development of the Earth Science Collections. Raquel is on the advisory board of the Association for the Study of Jewelry and related Arts, board of the directors for the Women Jewelry Association, the Gemstone and sustainable development knowledge Hub, and the Society of Mineral Museums Professionals; she is also an Associate Editor of GIA and GEM-A.

The first gem quality pegmatite discovery in North America correspond to Mt. Mica, Main, 1820. This pegmatite, previously characterized as a complex type of the rare-element class belonging to the LCT family- elbaite subtype, is well known for its colorful and highly desirable gemstone tourmalines, specifically the elbaite variety. Nowadays, tourmaline is considered an ideal candidate to study pegmatite environmental evolution and conditions as it monitors the evolution of the fluids during its formation. In this study, 50 elbaite gemstones from that first discovery, have been analyzed by non-destructive/no sample preparation technique, Micro Confocal Raman Spectroscopy, in combination with laser ablation, developing an ideally suited correlation study specially for the use with rare and valuable samples. The strong correlation between the OH-stretching vibrations (3350- 3600 cm-1 wavelength) and Y-site substitutions by Fe2+, Fe 3+ and Mn2+ allowed us to characterize four different elbaite groups and place them in agreement with their dominant chromophore and coloring mechanism: pink, light color, green and blue. Elbaites are strongly enriched in Cs and Ta; normalized partition coefficient patterns display a typical fractional crystallization sequence of decreasing temperature and increasing H2O content from blue, to green, to light color, to pink and a chemical evolution from a LCT-REE-Li-elbaite to a LCT-miarolitic-Li-lepidolite end member in the miarolitic cavities. Consequently, this combined methodology of Micro Confocal Raman Spectroscopy and laser ablation studies of gemstone varieties of a mineral supergroup, not only provides refinements on crystal structural constraints but also provides insights about their formation conditions, a field with great potential in applied gemology and the study of gem deposits.

Crystallization and Evolution in Magmatic Systems, from Small to Big

Ryan Currier, Ph.D.
Associate Professor of Geology, Department of Natural Sciences, University of West Georgia

Ryan Currier is a fan of all things magmatic. His research focuses on understanding the processes involved in magmatic plumbing systems, specifically regarding flood basalt provinces. Ryan gained a B.Sc in Geological Sciences from Michigan State University, and a M.A and Ph.D from Johns Hopkins University. He enjoys learning new things, he keeps his office messy, and his relationship with coffee may be unhealthy.

Crystallization is the end of the line for all magmas, and is as unavoidable as taxes are for humans. Still, not all magma bodies undergo the same crystallization process. The main variants from system to system are cooling rate, style of intrusion assembly, and whether crystals and liquid separate. With these relatively simple processes a great breadth of igneous diversity is possible, and can be observed across intrusions of various sizes. In this presentation, these magmatic processes will be explored with emphasis placed on surveying a variety of igneous systems. 

A Wet Moon: Lessons from the Apollo Samples

Molly McCanta, Ph.D. Gerald Sisk Associate Professor of Mineralogy and Petrology, Department of Earth & Planetary Sciences, University of Tennessee

Dr. McCanta received her BS from the University of Oregon and her MS and PhD from Brown University. Following that she was a post doc at the Lunar and Planetary Institute and Caltech. She is now the Gerald Sisk Associate Professor of Mineralogy and Petrology at the University of Tennessee Knoxville where she runs the experimental petrology lab and studies the mineralogic record of igneous processes on Earth, Venus, the Moon, Mars, and assorted meteorite parent bodies.

For decades the Moon was thought to be totally dry. Recent analysis of Apollo samples and lunar meteorites have proven that not to be the case. This talk will focus on water-repositories in lunar materials and how the presence of water changes lunar geologic evolution theories.

Skarn – Nature’s Mineral and Gem Laboratory

Larry Meinert, Ph.D. Affiliate Research Professor, Colorado School of Mines; Editor in Chief, Economic Geology

Larry Meinert is a leading expert on skarn deposits, source of many of the world’s metals, minerals, and gems.  Currently he is an Affiliate Research Professor at the Colorado School of Mines and Editor in Chief of Economic Geology, the premier international scientific journal concerning mineral resources. He also is President of the Geological Society of Washington. Previously he was at the US Geological Survey where as Deputy Associate Director of Energy and Mineral Resources he oversaw the research activities and budgets of hundreds of scientists across the country. His early academic career was as a professor at Smith College and Washington State University where he managed research laboratories and advised dozens of postdoctoral scientists and Ph.D., M.S., and B.S. students engaged in cutting edge mineral resource research. He earned a Ph.D. degree in geology from Stanford University and B.A. from Carleton College. In his spare time, he operates a small home winery specializing in a barrel-fermented Bordeaux-style blend of Cabernet Sauvignon, Carmenere, and Malbec. He also is a photographer, avid cook, and runs marathons. He has qualified for and run the Boston Marathon twice, in addition to most of the military (Air Force, Army, Marine Corps, and Navy) and scenic (Big Sur and St. George, Utah) marathons in the United States.

Skarns form at the contact between an igneous intrusion and reactive wall rocks such as limestone. The strong temperature and compositional gradients between the hot magma and the cooler wall rocks lead to a series of geochemical reactions resulting in the formation of calc-silicate minerals, such as garnet and pyroxene, as well as the deposition of numerous elements of economic importance such as copper, gold, iron, tin, tungsten, and zinc.  Some of the skarn minerals are large and beautiful, thus attracting the attention of mineral collectors around the globe. This lecture will describe how skarns form, showing examples of some of the world’s major deposits, and illustrated with photos of some beautiful crystals.


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