Just beneath the grapevines of a century-old winery in Put-in-Bay lies a surprise so dazzling, you’d swear it belongs in a fantasy novel.
Down a staircase and through a narrow passage, the walls begin to shimmer, and suddenly, you’re standing inside a giant crystal. Welcome to Crystal Cave, the world’s largest known geode, and one of Ohio’s most unexpectedly magical destinations.
A Chance Discovery
Back in 1897, workers at Heineman Winery were digging a well when they hit something strange: an open space deep underground, its walls glittering with icy-blue crystals. The family patriarch, Gustav Heineman, had only hoped to tap into a water source. Instead, he uncovered a 30-foot-deep limestone cave completely lined with celestite crystals, some stretching up to 3 feet wide.
They had found a geological marvel, formed over millions of years, hiding in plain sight beneath South Bass Island.
From Fireworks to a Lifeline
Celestite isn’t just beautiful, it’s also full of strontium, the element that gives red fireworks their signature color. For a while, the cave’s crystals were harvested for pyrotechnics, slowly hollowing out what had been an even more cramped space.
But when Prohibition hit and wineries across the country closed their doors, the Heineman family pivoted. They opened the cave to visitors, offering tours of the glittering chamber, and that decision may have saved the winery. While their competitors shuttered, Heineman’s stayed afloat on the curiosity of tourists and the quiet strength of a cave unlike any other.
Welcome to the World’s Largest Geode
Stepping into Crystal Cave today still feels like entering another realm. The air cools instantly. The light dances on celestite formations, their soft hues glowing in blues, silvers, and whites. It’s surreal, otherworldly, and surprisingly peaceful.
Photos don’t quite do it justice. You have to be there, looking up at three-foot-wide crystals arcing over your head, to really grasp the scale and sparkle of the place.
Tour the Cave and Sip Some Local Wine While You’re At It
Crystal Cave is owned and operated by Heineman Winery, still family-run after five generations. A combo tour gets you access to the cave and the historic wine cellar, plus a 5-ounce pour of wine or grape juice to enjoy afterward. This is a place where geology meets a good glass of pink Catawba.
Tour Info
Crystal Cave is open to visitors from April 21 through October 26. From April 21 to May 2 and again from October 1 to 26, tours run daily from 12 to 5 p.m. During peak season, May 3 through September 30, hours extend to 11 a.m. to 6 p.m. Monday through Saturday, and 12 to 6 p.m. on Sundays.
Admission is $14 for adults and $8 for children ages 6 to 11, while kids under 6 tour for free. The cave is located at Heineman Winery on South Bass Island in Put-in-Bay, and wine can be shipped year-round. For full details, visit heinemanswinery.com.
The Bottom Line
Whether you’re a geology nerd, a curious traveler, or just someone who loves discovering the unexpected, Crystal Cave is worth the trip. It is not just the world’s largest geode, it is a piece of Ohio history, science, and magic, wrapped into one sparkling underground stop.
Next time you’re planning a Put-in-Bay adventure, go beyond the wineries and lake views. Wander 40 feet beneath your feet, and let a cave of crystals remind you that sometimes, the best surprises are hidden just out of sight.
