[cid:image001.jpg@01D988A4.D4E14F10]Friends of Mineralogy-Virginia Chapter Speaker Series Rubies are red, sapphires are blue: understanding color phenomena in gem corundum Speaker: Dr. Aaron Palke, Senior Manager of Colored Stone Research, Gemological Institute of America Date: 25 May 2023 Time: 7:00 pm EST Registration: https://us02web.zoom.us/meeting/register/tZMtdOGrqz0uE9Mrg-6NgobJoWJWg5z2BC1_#/registration [cid:image002.jpg@01D988A4.D4E14F10][cid:image003.jpg@01D988A4.D4E14F10] The various colors of gem corundum (ruby and sapphire) are well understood from a chemical level. The trace element chromium colors ruby red while pairs of iron and titanium produce blue in sapphires. But the world of corundum color is much richer than this simple view of things. This presentation will provide an overview of color in gem corundum as well as dealing with treatments and other unusual color phenomena in these precious stones. How are people treating rubies and sapphires to enhance their color and what is going on in a physical and chemical level? Why do some sapphires change color with simple exposure to light? All of these questions and more will be addressed in this talk. [cid:image004.jpg@01D988A4.D4E14F10] Dr. Aaron Palke developed an interest in minerals and gemstones searching for agates and other minerals in eastern Montana. He was particularly struck by the geographic distribution of mineral and gem deposits and geological features, for instance, why are there mountains and an abundance of mineral deposits in Montana but not in his home state of Oklahoma? These questions led Dr. Palke to pursue a formal education in geology, obtaining a Bachelor of Science degree from The University of Tulsa and a Ph.D. from Stanford University. Dr. Palke began his gemological career as a Postdoctoral Research Associate at the Gemological Institute of America where he is now the Senior Manager of Colored Stone Research<https://www.gia.edu/gia-researcher-aaron-palke>. In this role, Dr. Palke leads GIA’s research efforts into geographic origin determination for rubies, sapphires, emeralds and other colored stones as well as improving criteria for identification of treatments for colored stones. Dr. Palke is a regular contributor to Gems & Gemology and serves on the journal’s editorial review board. === This presentation will be recorded and posted on YouTube. It, and all previous Speaker Series talks, can be found online at https://www.youtube.com/channel/UCVXiDsPBpOIZ2Qw3L8XH3VQ/videos. === Friends of Mineralogy Virginia (FMVA) Speaker Series provides the highest quality lecture experiences with a personal atmosphere. Our speakers are some of the leading experts in their fields and interests and are ready to share their passion with our members. FMVA hopes to provide a platform where the academic communities, industry professionals, and the public can engage with one another for the shared passion of rocks, minerals, and geology. We strive to find an appropriate mix of lectures that are easily accessible for all ages and levels of knowledge.