Facebook stock closed at 38.23 on its first day of trading, and is having a rocky week. Friends and co-workers have organized pools to bet on where it will be some weeks hence when shares become readily available to the general public.

If the Facebook IPO leaves you with some spare change, or you can’t stomach so much volatility, consider investing in minerals. As a collectible, they’re so hot right now that Dallas-based Heritage Auction Galleries created a new department for them in March and plans to start holding bi-annual mineral-only auctions starting this year.

The finest specimens of tourmaline, rhodochrosite and crystallized gold are fetching more than $1 million apiece—about five times what they sold for five years ago, says James Walker, a long-time dealer who also works as co-director of fine minerals for the auctioneer. Some really gorgeous rocks were estimated to fetch more than $250,000 apiece at an auction they held in New York May 21, but haven’t yet sold. (Post-auction bidding is open until June 4.) You can see these items and others in the photo gallery here.