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STANDARDS
CCSS: 8.G.C.9
TEKS: 8.7A
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One Giant Geode
Hector Garrido Guil/CSIC
Visitors to southern Spain can now step inside an otherworldly rock formation: a giant geode. The attraction near the town of Pulpí recently opened to the public. It’s one of the largest crystal-filled rocks ever discovered.
The geode began forming millions of years ago as mineral-rich water seeped underground. The water slowly evaporated, leaving behind crystallized minerals. Some of the crystals grew to be 7 feet long!
To enter the geode, people squeeze through a small opening at one end. “The first time I stepped inside, my heart raced because I was seeing something incredible,” says Javier García Guinea, a geologist at the National Museum of Natural Sciences in Madrid, Spain.
The Pulpí geode is shaped approximately like a cylinder. It has a height of 26 feet and a diameter of 5.6 feet. What is the volume of the geode, rounded to the nearest tenth? (Hint: Volume of a cylinder is πr2h.) Record your work and answer on our Numbers in the News answer sheet.
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