Helium is a byproduct of the natural gas industry. Its most important use is in MRI.
Quartzite is metamorphic rock formed when sandstone is subjected to heat and pressure.
Pyroxene Minerals are a group of chain silicate minerals found in igneous and metamorphic rocks.
Where Are the Canary Islands? Off the northwest coast of Africa, 60 miles west of Morocco.
Phytoplankton Blooms are caused by an explosive growth rate of plankton in surface waters.
Bear Attacks - Knowing how to react to a bear encounter or attack could save your life.
What Is Luster? Luster is the light-reflecting characteristics of a mineral specimen.
Zircon is the primary ore of zirconium and a gemstone that is available in many colors.
Sand is a diverse material. This gallery includes photos of sand from around the world.
Crystal Habit is the external shape displayed by a crystal or an aggregate of crystals.
Rocks - Galleries of igneous, sedimentary and metamorphic rock photos with descriptions.
Hardness Picks - Test for hardness with precise and easy-to-use hardness picks.
Mohs Hardness Scale is a set of reference minerals used for classroom hardness testing.
Largest Hurricanes Are they determined by wind speed, value of damage, most deaths?
Coquina - A porous limestone composed almost entirely of fossil debris.
Rock & Mineral Kits The best way to learn about rocks and minerals is with specimens!
Mount Etna - The most active volcano in Europe continues an eruption that started in 2001.
The Acid Test - Geologists use dilute hydrochloric acid to identify carbonate minerals.
Volcanic Explosivity - Rating volcanic eruptions based upon the volume of tephra ejected.
Map of the Oceans - showing the Atlantic, Pacific, Indian, Arctic and Southern Oceans.
World Record Lightning - this lake has more lightning than any other place in the world.
Blue Flames and the largest highly acidic lake in the world at Kawah Ijen Volcano.
Ruby and Sapphire are the 2nd and 3rd most popular colored stones in the United States.
Types of Maps - Explore some of the most popular types of maps that have been made.
Teacher Resources - K-12 resources for teaching about earth science.
Tallest Tsunami - A wave with a run-up height of 1720 feet occurred in Lituya Bay, Alaska.
Largest Earthquake ever recorded - Magnitude 9.5. Chile, 1960.
Rock Tumblers - All about rock tumblers and rock tumbling. Read before you buy a tumbler.
Mars Meteorites Mars rovers have found dozens of meteorites while exploring the red planet.
Solar System Volcanoes - Earth is not the only location of volcanic activity.
What is the San Andreas Fault? Map, photos and description of the fault.
Geology Tools Rock hammers, field bags, hand lenses, maps, hardness picks, gold pans.
Cinnabar - the only important ore of mercury. Used in pigments until its toxicity was realized.
Fool*s Gold is a name used for pyrite when its brassy color fools people looking for gold.
Utica Shale is a major source of oil, natural gas and natural gas liquids in PA, OH and WV.
Pictures of Opal - A collection of different types of opal from all around the world and Mars too!
Morganite is an orange to pink gemstone, a variety of beryl, that is growing rapidly in popularity.
Minerals - Descriptions, photos, articles, properties and uses for common minerals.
US Diamond Mines - Did you know that diamonds have been mined in the United States?
Obsidian - the volcanic rock that cools so quickly that it becomes a natural glass.
Ticks are a problem for geologists in some areas. Learn to recognize and avoid them.
Mined in America - Small mines in the United States produce a diversity of beautiful gemstones.
Free Google Earth software allows you to browse seamless world satellite images. Free.
Mineraloids are amorphous naturally-occurring inorganic solids that lack crystallinity.
Copper Kills COVID-19 and many other pathogens to limit the spread of disease.
Hawaii*s Next Island could be growing in the Pacific Ocean right now. Its name is Lo*ihi.
Soapstone is a metamorphic rock with properties that make it suitable for a variety of projects.
Charoite is a purple silicate mineral, found only in Russia, used as a gem material.
The Science of Fireworks Learn how the colors and shapes are created.
California Earthquake Maps - A collection of isoseismal maps for earthquakes in California.
Rhodochrosite - a manganese mineral used as an ore, a pink gem and an ornamental stone.
Range of Bear Species - Where you might encounter different types of bears.
Deepest Point in the Ocean The deepest point in the ocean is in the Mariana Trench.
Labradorite is a feldspar mineral that sometimes exhibits an iridescent play-of-color.
Corundum is the third hardest mineral. It is also the mineral of ruby and sapphire.
The Many Uses of Gold - Unique properties make gold one of the most useful metals.
Colored Diamonds are diamonds with a noticeable body color. They can sell for over $1M/carat.
Novarupta - The most powerful volcanic eruption of the 20th century occurred in the U.S.A.
Birthstones are gems assigned to the month of a person*s birth. They are popular gifts in the U.S.
Wall Maps - Wall maps of the world, continents, states and the USA.
Methane Hydrate deposits contain more fuel value than all other fossil fuels combined.
How Are Hurricanes Named? There is a plan for naming tropical storms.
What is Geology? The study of Earth materials, structures, processes and life over time.
The Rock Used to Make Beer - Geologists are beer experts and should know about this rock.
Ethiopian Opal - The new opal heavyweight that might give Australia a run.
Azurite - Used as an ore of copper, a pigment, ornamental stone and gem material.
Granite - The intrusive igneous rock that underlies continents and countertops.
Geodes look like ordinary rocks on the outside but can be spectacular inside!
Shale - The rock that has quickly transformed the oil and gas industry.
The East Africa Rift System - The extensive fault system that is tearing Africa apart.
Geology Books - A variety of books for reference, field trips, reading and more.
Diamond Misconception - Many people think that diamonds form from coal. Not True!
Diamonds - Learn about the properties of diamond, its many uses, and diamond discoveries.
Gemstones - Colorful images and articles about diamonds and colored stones.
Portable UV Lamp - Short and long wave UV for fluorescent mineral viewing.
Emerald is the most popular green gemstone in the United States and most of the world.
What Is The Moho? The Mohorovicic Discontinuity is the mantle/crust boundary.
Grape Agate is a popular mineral specimen with the color and the shape of a bunch of grapes.
What Is Earth Science? The study of Earth and its neighbors in space. Learn more!
Sliding Rocks Mystery - What causes these rocks to slide across a playa in Death Valley?
Pandora Jewelry One Love Cubic Zirconia Ring in Sterling Silver - The DeLorme Atlas is an entire state of topo maps in one convenient book.
Petrified Wood is a fossil that forms when silica replaces and infills the cavities of wood.
Gem Silica is a blue chalcedony colored by copper. It is the rarest and most valuable chalcedony.
Rhyolite An extrusive igneous rock with a high silica content, produced from granitic magma.
Meteorites - Rocks that were once parts of planets or large asteroids.
Chalk is a variety of limestone formed from fine-grained marine sediment known as ooze.
Premium Anchor Rope Double Braided Boat Anchor Line 100 ft Black - a metamorphic rock and the most popular blue opaque gemstone in history.
Expansive Soil causes more damage than floods, hurricanes & tornadoes combined.
Tallest Mountain - Everest has rivals in tallness, altitude and distance to the center of Earth.
Plate Tectonics - Articles and maps about plate tectonics and the interior of Earth.
Crater of Diamonds - The only diamond mine in the world where you can be the miner.
Gold Pans and Panning Kits - classifiers, snuffer bottles. Learn how to pan for Gold.
Ant Hill Garnets - tiny gems that ants haul to the surface and discard on their anthill. Honest!
Hand Lens A 10-power folding magnifier in a metal case. A frequently used lab and field tool.
Types of Volcanic Eruptions - A description of the most common eruption types.
World*s Largest Diamonds Records for the largest rough, faceted and carbonado diamond.
Debris Flows are moving masses of loose mud, sand, soil, rock and water.
Rock Art - People have been marking on rocks for thousands of years.
Fire Opal is a transparent to translucent opal with a yellow, orange or red background color.
Citrine is the transparent variety of quartz with a yellow to orange to reddish color.
Rare Earths - Special materials used in electronics, defense, medical & many other products.
Storm Surge can be the most damaging and deadly aspect of a hurricane.
Cave of the Hands is a cave where ancient people painted hands about 9000 years ago.
Extraterrestrial Gems - A number of materials from space are used as attractive gems.
Waterproof Paper - Don't take chances with your field notes and maps. Use waterproof paper.
Turquoise - A bluish-green gem material that has been used for over 6000 years.
Herkimer Diamonds Doubly-terminated quartz crystals used as specimens and gems.
Ilmenite - The primary ore of titanium and source of most titanium dioxide.
Rock Salt is a sedimentary rock composed of the mineral halite. It has many uses!
Field Courses - Over 80 field courses for undergraduate geology students.
Olivine - Abundant in Earth*s mantle. A constituent of meteorites. The gem peridot.
Rocks on Mars Many of the rocks found on Mars are not very different from Earth rocks.
10 Gemmy Facts About Spinel - Is spinel the world*s most overlooked gem?
Volcanoes - Articles about volcanoes, volcanic hazards and eruptions past and present.
What is a Maar? The second most common volcanic landscape feature on Earth.
Angel Falls in Venezuela is the tallest waterfall in the world - it is 3212 feet tall.
How did the Hawaiian Islands Form? The power of a moving plate over a stationary hot spot.
Know the Rules before removing rocks, fossils or minerals from public or private property.
Tourmaline - an extremely colorful mineral and gem material.
Gifts That Rock - What are the most popular gift items in the Geology.com store?
100+ Gems - Photos of over 100 beautiful gems ranging from the popular to the obscure.
What is a Geyser? Photos and information about geysers in many parts of the world.
Lightning Strikes Map by NASA shows the worldwide distribution of lightning activity.
Tanzanite was unknown until a few decades ago but it has erupted into wide popularity.
Chalcopyrite - The most important ore of copper for over five thousand years.
Hematite - The most important ore of iron. A source of mineral pigment since prehistory.
Fluorescent Minerals and rocks glow with spectacular colors under ultraviolet light.
The Uses of Marble are numerous and diverse. You will be surprised by how it is used.
Largest Volcano - That title is shared by Tamu Massif, Mauna Kea and Ojos del Salado.
Coal Through a Microscope - Coal is more than a black rock. It is THE most interesting rock.
Horizontal Drilling has opened new resources and significantly improved productivity.
Peridotite is a chromite host rock, a source of diamonds and a possible carbon dioxide sink.
Homeowners Insurance might not cover earthquake, hurricane and other geohazard damage.
Mount Vesuvius - geology, history, maps, facts and more about the Vesuvius eruptions.
Names Used for Great Britain, British Isles, United Kingdom, and Ireland. What they mean.
Talc is a soft mineral used in cosmetics, paper, paint, ceramics and many other products.
The Unsung Mineral Hero - and the commodity upon which almost everything is built.
Mineral Rights - Who owns the minerals under your land? Who wants to buy them?
Cinder Cones are the smallest, simplest, and most common type of volcano.