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Explore Giant Crystal Caves

Scientists Exploring the Giant Crystals in the Naica Caves

Does your kid love rocks and crystals? Here are some fun facts you can share with them to kickstart their imagination and explore this stunning natural phenomenon.

What are crystals?

While most of us think of crystals as transparent (there’s your kid’s word for the day!), crystals can be anything from quartz to salt, and even snow! What all these crystals have in common is an extremely well-structured molecular structure with a repeating order.

But let’s talk about the largest crystals in the world!

Deep underground in Northern Mexico, two brothers searching for silver and discovered what is now known as the Cave of the Crystals. The cave has three massive chambers large enough to drive a car through and has some of the biggest selenite crystals ever found — some as large as 36 feet long and weighing as much as 55 tons. That is as long as a telephone pole and weighs more than nine elephants!

These crystals have been growing for half a million years. They were formed by gypsum-rich water heated by a pool of magma 2—3 miles below the surface. Gypsum is a mineral that is in everything from shampoo to toothpaste, cement, chalk, and selenite crystals.

How did the brothers find this amazing cave of crystals? The cave was drained in 1975 for mining operations, but because of the pool of magma, the temperature in the cave stays at 100°—150°F. That’s too hot for people to stay inside for more than a few minutes at a time, but it was long enough for them to make their amazing discovery!

To study and photograph the crystals, scientists use special refrigerated suits and breathing gear.

The problem with draining the water was it meant the crystals would stop growing. In 2017, the cave was allowed to flood once more once the scientists had completed their research, and the crystals are now able to continue growing. Who knows how large they will be in another half million years!

Want to learn more about crystals? Check out our crystal identification guide.

You can also grow your own crystals and dig for crystals in our award winning products.