Now, in the cave, a team of scientists and explorers is conducting research and working on a documentary. Stein-Erik Lauritzen, a professor of geology at the University of Bergen in Norway, is retrieving samples for uranium-thorium dating. His preliminary research suggests the largest of the crystals are about 600,000 years old. Penelope Boston, an associate professor of cave and karst science at New Mexico Tech, searches for microbes that might live among the crystals. In some of them, tiny bubbles of suspended fluid—the kind García studied—sparkle in our lights. They are little time capsules: Italian scientists led by Anna Maria Mercuri extracted pollen that may have been trapped within these inclusions. The grains appear to be 30,000 years old and suggest that this part of Mexico was once covered not by desert but by forest.
One long, slender beam bears a deep scar from where someone tried to cut through it. I imagine a miner dripping and alone in the smothering silence, his weak headlamp bouncing with each saw stroke. Collectors might pay tens of thousands of dollars for a crystal from this cave. Whoever he was, he quit before he could sever the crystal, and mine owners later installed a heavy steel door to deter looters. So far it has worked, but who knows if it will last. Miners, after all, have access to drills and explosives. And while mining and construction projects can be halted to save archaeological relics, minerals in Mexico have no such protection.
The crystals could also be threatened by the lack of water. When the cave was filled, water helped support and preserve the beams. Now, with the cave empty and open to air, they may over time bend or crack under their own weight and become dull, as gases such as carbon dioxide wash in. The director of the mine told me his company, Peñoles, is dedicated to preserving them, but the company's main interest isn't crystals, and the basic activities of mining—blasting, trucks stirring up dust—threaten the gallery. Badino and others hope to convince the company to do more (lobbying for UNESCO World Heritage status has been mentioned), but so far the crystals exist in limbo, probably more famous outside Mexico than within.
We stop for a moment to rest. Everything around us glitters; it is as though we are standing inside a star. Badino turns, and the lines crease at the corners of his eyes. He pulls his mask away. "You know," he says, smiling, "there would be worse places to die."
Cathedral, star, tomb. We look for something to anchor the otherworldly in the familiar. After half an hour we depart, soaked in sweat, our veins throbbing, and a visiting filmmaker asks what it was like. I have a little trouble. He nods, understanding.
"Es como un sueño de niño," he says. "It is like a child's dream."