In 2000, miners 300 meters beneath the Mexican desert broke into a chamber filled with translucent crystals more than 11 meters long. The Cave of the Crystals at Naica contains some of the largest natural crystals ever found. Their size came not from a violent geological event, but from an almost perfectly stable underground environment that may have persisted for hundreds of thousands of years. Scientists eventually measured crystal growth so slow that a sheet of paper’s thickness could take roughly two centuries. The mechanism is well understood. The exact age, interruptions in growth, and why Naica remained stable for so extraordinarily long are not. ─────────────────────────────── IN THIS EPISODE — The discovery of giant selenite crystals beneath Naica — The narrow temperature window that allowed them to grow — A crystal growth rate measured in centuries per millimeter — What remains uncertain about their age and unique size SOURCES Geology — García-Ruiz et al., 2007 Proceedings of the National Academy of Sciences — Van Driessche et al., 2011 AAAS Annual Meeting — Penelope Boston, 2017 ─────────────────────────────── Narration in this episode is AI-assisted. Research, writing, and editorial decisions are human. Reality Is Strange — real phenomena, verified, and stranger than they should be.

The Crystals That Took a Million Years to Grow

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