Weird Places: Mexico's Giant Crystal Cave

The Giant Crystal Cave in Naica, Mexico, was discovered in 2000 by miners. It contains the largest crystals ever found, formed under extreme conditions of high temperature and humidity. The cave's environment is inhospitable, making research challenging. The crystals are made of selenite, a form of gypsum, which formed over half a million years due to the slow transformation of anhydrite in water. Other caves in the area have smaller crystals due to faster cooling. The cave's unique conditions allowed for the growth of these massive crystals, and they may continue to grow if the cave is reflooded.

What was the initial purpose of the mining company when they started pumping water out of the cave in Naica, Mexico?

• To discover new minerals

• To explore the cave's interior

• To find gold

• To extract lead, zinc, or silver

Why can humans only survive for about 10 minutes in the Giant Crystal Cave without protection?

• Because of dangerous wildlife

• Because of the high temperature and humidity

• Due to toxic gases

• Due to the lack of oxygen

What special equipment do scientists use to study the Giant Crystal Cave?

• Heat-resistant suits

• Radiation suits

• Refrigeration suits

• Diving suits

What is the key factor that allows anhydrite to transform into gypsum in the Giant Crystal Cave?

• Pressure

• Humidity

• Light

• Temperature

What will happen to the crystals in the Giant Crystal Cave when the mine eventually closes?

• They will stop growing

• They will start shrinking

• They will continue to grow

• They will dissolve