The Mid-Hudson Valley Gem & Mineral Society is hosting its annual gem, fossil, mineral, and jewelry show and two-day sale at Gold’s Gym. This year’s show theme is “The World of Crystals.” At the event, there will be 30 dealers to shop from, a lapidary (gem-cutting) demonstration, and rock and mineral displays set up by the Vassar Geology Museum and MHVGMS members. Kids will receive six free rocks at Glitter Mountain and can also sluice for treasure at Garnet Gulch. Additionally, high school students can participate in the Earth Science Scavenger Hunt.