We’ve had a mystery rock in our house since my 11-year-old spent a week at my sister’s place Up North in Michigan

It’s not a rock, really, but a geode, an outer shell that’s hiding crystals and mineral formations inside.

The word “geode” comes from a Greek word meaning “earth-shaped.” While a geode looks pretty much like a rock, it doesn’t feel very rock-like when you hold it. The geode feels lighter than what you’d expect for its size, and its surface is much softer to the touch than that of a typical rock.

The geode was a gift to Will from my sister’s Up-North neighbor, Alice.

“Only God’s seen inside this,” Alice told Will when she handed him the geode. “When you open it, be sure to send me a picture of what’s inside.”

Since then the geode’s lived in our house, waiting to be cracked open like an egg with a mystery inside instead of a yolk.

We didn’t want to take a sledge hammer to the geode, fearing we’d ruin the treasure inside. Will checked with the local jeweler to see if he had access to tools that could cut the stone open; he didn’t, but directed Will to a store in Ann Arbor in the hopes that someone there might be able to saw it open, but that didn’t pan out.

Then, Will had a brainstorm.

“Why don’t we check at Brighton Stone,” he asked.

Why didn’t I think of that? Brighton Stone is a local business that specializes in all sorts of stone, for indoor or outdoor use, and has all the equipment it needs to do all manner of stonework.

It took one of the employees just a minute or two to slice through the geode with a wet saw. We stood off to the side and watched as the noisy saw did its work.

When the geode was finally cut in two, the man held it out for us to see.

It was amazing, really, to finally see what’s been hiding inside the geode for who knows how many years. The geode’s hollow center was filled with short, stubby, grape-like formations that took maybe thousands of years to form.

It’s just a bit awe-inspiring to stand witness to the power of the universe illustrated in such a small way. With the geode, it’s kind of like a pearl taking shape inside an oyster. The outer shell of the geode forms, trapping mineral-rich water inside. Temperature, pressure and the minerals in the water combine forces to create a natural masterpiece every bit as individual  as every single human being on earth.

Looking inside the geode was what I imagined it might be like to see the center of the universe, like holding a tiny solar system in my hand.

Somehow, I felt instantly lucky at being among the first to see the secrets the geode nurtured for so long as it waited for the perfect, kindly woman to pass it on to an inquisitive young boy who’d figure out how to safely crack it open and reveal the secret inside.

“This is just so cool,” Will said as he held the geode. “But I’ve got to wash my hands. If this thing’s as old as I think it is, it’s got a lot of dirt and germs on it.”