The Sword-Like Giants of Naica: How Earth's Deepest Crystals Grew
Deep beneath the Chihuahuan Desert of northern Mexico, miners working in the Naica lead-zinc-silver mine in the year 2000 made an astonishing discovery. Breaking through a limestone wall 300 meters underground, they stumbled into a cavern that looked like the fortress of a mythical giant. The chamber, now known as the Cave of Crystals (Cueva de los Cristales), was filled with some of the largest natural crystals ever found on Earth. Towering pillars of translucent white gypsum, resembling massive swords, spanned the cavern, with some measuring up to 39 feet (12 meters) in length and weighing as much as 55 tons. Understanding how these gargantuan structures grew requires examining a perfect storm of subterranean chemistry, geothermal heat, and immense spans of undisturbed time.
- Geothermal:
- Relating to or produced by the internal heat of the Earth.
- Gypsum:
- A soft, natural mineral made of calcium sulfate that often forms dramatic crystals.
- Supersaturated:
- A chemical state where a liquid holds more dissolved minerals than it normally could.
- Precipitate:
- The process where dissolved minerals separate from water and form solid crystals.
- Translucent:
- Semi-transparent; allowing light to pass through but scattering it so that objects on the other side are not clearly visible.
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- 1In what year and at what depth underground did miners discover the Cave of Crystals?
- 2How large and heavy can the largest gypsum crystals in the Naica cave get?
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About this explanatory article passage for Middle School
“The Sword-Like Giants of Naica: How Earth's Deepest Crystals Grew” is a explanatory article reading passage about Geology and Mineralogy, written for Middle School. It takes about 4 minutes to read (597 words) and comes with an interactive quiz and a printable worksheet with comprehension questions and an answer key.