Silica gel is a form of silicon dioxide, a naturally occurring mineral. As a desiccant, it helps prevent degradation or spoilage of products that are sensitive to moisture. That's why you'll find the sachets in everything from a new handbag to a package of beef jerky.
Kitchen uses for silica gel are practically endless. We have the packets stashed in our spice drawer, in containers of dried fruits and herbs, and with stored kitchen tools like cast iron pans, cookie cutters, and mason jar rings.
By the way, what would happen if you ate silica gel? Nothing, says Slate. While we'd still exercise caution (and toss any open packets), it's good to know that it's pretty safe to have around the kitchen.