If you’re heading to any weddings this summer, keep an eye out for the latest dessert craze: geode cakes.

Not to be confused with the recently trending galaxy cakes, geode cakes are more of the earthly variety—cakes that look like they have the crystallized cross-section of an amethyst or the like baked right into it.

Intricate Icings Cake Design

Of course, a giant rock isn’t baked into the cake—the mineral-inspired culinary artwork is all entirely edible.

Baker Viki Kane, owner of Just a Little Dessert Co. in southern California, perhaps sparked the wedding-geode cake trend back in 2015, when she created an edible geode-like cake topper for a baking competition in Louisiana.

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“I’ve always loved rocks and geodes—who doesn’t? It was a last-minute idea, what would look cool on top of this cake? In the cake world, so much has been done, it’s hard to come up with a different technique that’s never been seen before,” Kane says.

Courtesy Viki Kane

After getting requests, Kane soon developed a tutorial for the technique, popular with other cake artists. “I thought it was a blip,” she says, “but it just kind of snowballed.”

Denver-based cake artist Rachael Teufel, owner of Intricate Icings Cake Design, was perhaps the first to bake an edible geode into the cake itself earlier this year, when she baked a cake for free for a friend to celebrate a new wedding-planning service and venue.

The favor paid off: After she posted a video of the cake—a purple-and-gold amethyst design, made with rock candy, food coloring and edible gold paint—it went viral, growing her Facebook likes from 15,000 to more than 65,000 today.

“Have you ever had rock-candy sticks? That’s exactly what it is—just loose candy, except you’re not forming onto a stick,” explains Teufel, who also offers a tutorial. To achieve that sense of layering in the geode design, she also uses three sizes of the candied sugar: a rock candy size, similar to what you’d find on a stick; crystallized sugar, similar to the size of Pop Rocks; and granulized, like table sugar. The colors come from edible food colors that are airbrushed on.

The couples who order the cake always have a good story, Teufel says. “They are geologists themselves, or have a family who is big into nature or geology—just this weekend, I made one for a family who lives in a mining town in western Colorado.”

And if you want to get in on the trend at home, there’s no need to bake a whole wedding cake: Los Angeles-based food stylist and designer Alana Jones-Mann, another early entry in the geode-dessert field, makes these gorgeous gemstone cupcakes and cookies.

Geode cookies Alana Jones-Mann

“At the time that I had made them, they definitely weren’t present in the party or baking world yet, but I would say there was buzz around crystals in the wellness world. I personally had been inspired by nature—a visit to the American Museum of Natural History’s Gem Room was what gave me the initial idea,” she says.

Jones-Mann admits the process is “technical due to the fact it requires patience, and a little experimentation” but she’s also encouraging, likening it to making homemade rock candy, or that experiment you may have done as a kid where you hang a string in sugar water for a week and patiently wait for the sugar to crystallize.

“It’s more of a science experiment than a baking project, and I hope people also find the joy in that process,” she says.