Gem, Mineral & Fossil Showcase, February 2 - 17, 2013. For two weeks every winter, the world meets in Tucson as it becomes a bustling, international marketplace of buyers and sellers at the Tucson Gem, Mineral & Fossil Showcase. The main event of this two-week showcase is the Tucson Gem & Mineral Show™ which packs downtown's Tucson Convention Center over the final weekend. This show attracts thousands and Tucson Parks and Recreation Leisure Classes showcases student and instructor projects in a display of jewelry and glass for the world to see and enjoy.