Geology

Waterfalls are mainly reliant on precipitation to keep flowing. Here are six famous waterfalls that slowed to a trickle when drought set in.

By Laurie L. Dove

Nutty Putty Cave, near Salt Lake City, Utah, was discovered in 1960 and sealed up forever in 2009. This is the story.

By Dave Roos

This beautiful pink quartz is found in numerous places throughout the world and is thought to be associated with unconditional love.

By Carrie Whitney, Ph.D.

Not all diamonds are found on dry land. Many turn up in sediments below the ocean's surface. You just have to know where to look.

By Mark Mancini

Not all deserts have sand and they're certainly not all hot. They're just extremely dry and have little vegetation. That means deserts are located all over the planet, including at super-high elevations.

By Sharise Cunningham

The Mohs hardness scale is used by geologists and gemologists as a way to help identify minerals using a hardness test. How does it work?

By Carrie Whitney, Ph.D.

This ancient rock, which forms above copper deposits, is beloved for its swirling patterns and vibrant green color. It's dazzled humans for millennia as jewelry and even in décor.

By Carrie Whitney, Ph.D.

Tanzanite is so rare, it is sourced from just 8 square miles in Africa. It was first discovered in the late 1960s and it burst onto the jewelry scene thanks to Tiffany & Co.

By Carrie Whitney, Ph.D.

There are caves all over the world, but some are in places that are hard to explore — hidden by rocks, ruins or even under ice. We've found seven secret caves you probably never knew existed.

By Stephanie Parker

This ancient rock adorns King Tut's coffin and the Sistine Chapel. And at one time it was more precious than gold. What is it about this deep blue rock that has drawn us in for centuries?

By Carrie Whitney, Ph.D.

It's found all over Earth — and Mars, too. It's the main source of iron but is also used in jewelry and painting. Get to know the amazing mineral hematite.

By Trevor English

Drones are helping researchers bolster scientific understanding of the ecology of a greening Arctic.

By Lesley Evans Ogden

One term might give you the impression of something grand and mysterious, while the other makes you think of claustrophobia-inducing environs that threaten human life. But what's the real difference?

By Nathan Chandler

Birds are — quite literally — living dinosaurs. Our quiz will test your knowledge of the fluffy, downy and winged dinos of the bygone Mesozoic era, from little Microraptor to the enormous Yutyrannus.

By Mark Mancini

The Pacific's Ring of Fire is a 25,000 mile long "ring" that's home to 75 percent of all the world's volcanic activity and 90 percent of the planet's earthquakes. So what makes this area so active?

By Mark Mancini

Not all fossils are found on dry land. In fact some of the most fascinating fossil finds in history have been submerged for centuries.

By Mark Mancini

"The 26th century" doesn't roll off the tongue as easily as "the 21st century" does. But that hasn't stopped us from imagining what our hometown planet will be like in a few hundred years. Any guesses?

By Robert Lamb

Mountain Lake in Virginia is best known for its starring role in 'Dirty Dancing.' But today, it's nothing more than a muddy pit that's all but dried up ... and geologists think they may know why.

By Stephanie Parker

Gondwana was a humongous landmass that persisted for 300 million years before it began to break up, forming all the continents in the modern Southern Hemisphere.

By Jesslyn Shields

The Earth is unique in the solar system because its surface is made of moving plates, which may enable the very existence of life.

By Patrick J. Kiger

Cultures all over the world have treasured turquoise for its color and rarity for thousands of years — from Native American jewelry and Aztec and Mesoamerican art to King Tutankhamun's death mask.

By Michelle Konstantinovsky

Many scientists believe that humans influence Earth at a rate so massive that a change to the geologic time scale is in order.

By Mark Mancini

Cobalt is associated with the color blue, but it's so needed for rechargeable batteries that the U.S. put it on the list of minerals it can't live without.

By Dave Roos

It's perhaps one of the strangest fossils ever discovered. We'll explain how it came to be 15 million years ago, and how hikers found it in the '30s.

By Mark Mancini

What's as strong as steel but half the weight; able to live in almost any body part and an important part of both airplanes and cake frosting? Would you believe, titanium?

By Dave Roos