Hematite - The most important ore of iron. A source of mineral pigment since prehistory.
Fluorescent Minerals glow with spectacular colors under ultraviolet light.
||Huge Diamond Deposit
The Largest Diamond Deposit in the world could be under Popigai Crater in Russia.
Mohs Hardness Scale is a set of reference minerals used for classroom hardness testing.
How Do Snowflakes Form? They start as tiny mineral crystals and change as they fall to Earth.
Geology.com News is updated several times each week. Read it here or receive email updates.
Pictures of Opal - A collection of different types of opal from all around the world and Mars too!
Rocks - Galleries of igneous, sedimentary and metamorphic rock photos with descriptions.
Minerals - Descriptions, photos, articles, properties and uses for common minerals.
Gemstones - Colorful images and articles about diamonds and colored stones.
Rock Glaciers - Masses of rock, ice, snow, mud and water that slowly flow down slope.
Homeowners Insurance usually does not cover the most common geologic hazards.
Diamonds - Learn about the properties of diamond, its many uses and diamond discoveries.
Plate Tectonics - Articles, maps, information about plate tectonics and the interior of Earth.
||Hawaiian Hot Spot
How did the Hawaiian Islands Form? The power of a moving plate over a stationary hot spot.
Geologist Tools - Visit our store for a large selection of field and laboratory tools.
|The Brewery Rock ?
The Rock Used to Make Beer - Geologists are beer experts and should know about this rock.
Fire Opal is a transparent to translucent opal with a yellow, orange or red background color.
Granite - The intrusive igneous rock that underlies continents and countertops.
Salt Domes - Columns of salt that move upwards because of their low specific gravity.
Shale - The rock that has quickly transformed the oil and gas industry.
Basalt - Most of the ocean basin and part of the continents are underlain by basalt.
||Land Below Sea Level
Land Below Sea Level - Did you know that dozens of land locations are below sea level?
||Find Minerals & Gems
Find Minerals and Gems - Dozens of sites where you can dig and keep what you find.
|Oil and Gas
Oil and Gas - Articles about oil and natural gas in the US and around the world.
Obsidian - the volcanic rock that cools so quickly that it becomes a natural glass.
||Volcanoes in Space
Extraterrestrial Volcanoes - Earth is not the only solar system body with volcanic activity.
Sliding Rocks Mystery - What causes these rocks to slide across a playa in Death Valley?
Ammolite is a fossil and a gemstone. It is shell material from fossil ammonites.
||Asteroid Impact Map
Asteroid Impact Map - Explore fifty of the most obvious asteroid impact craters on Earth.
Emerald is the most popular green gemstone in the United States and most of the world.
Rock Art - People have been marking on rocks for thousands of years.
|What Is Earth Science?
What Is Earth Science? The study of Earth and its neighbors in space. Learn more!
||Sea Level Rise Map
Sea Level Rise Map - A Google map that shows where flooding will occur as sea level rises.
Bear Attacks - Knowing how to react to a bear encounter or attack could save your life.
100+ Gems - Photos of over 100 beautiful gems ranging from the popular to the obscure.
Diamond Misconception - Lots of people think that diamonds form from coal. Not True!
||Google Earth - Free
Free Google Earth software allows you to browse seamless world satellite images. Free.
Pavlof Volcano is one of the most active volcanoes in North America and a threat to air traffic.
||Gems from Space
Extraterrestrial Gems - A number of materials from space are used as attractive gems.
Fossils - Learn about fossils and fossil discoveries around the world.
||Uses of Gold
The Many Uses of Gold - Unique properties make gold one of the most useful metals.
||Crater of Diamonds
Crater of Diamonds - The only diamond mine in the world where you can be the miner.
Turquoise - A blue to bluish-green gem material that has been used for over 6000 years.
Labradorite is a feldspar mineral that sometimes exhibits an iridescent play-of-colors
Volcanoes - Articles about volcanoes, volcanic hazards and eruptions past and present.
Mount Vesuvius - geology, history, maps, facts and more about the Vesuvius eruptions.
||US Diamond Mines
US Diamond Mines - Did you know that diamonds have been found in the United States?
Teacher Resources - K-12 resources for teaching about earth science.
Dowsing is a method used to find underground water that is rejected by most geologists.
||What is Geology?
What is Geology? - The study of Earth materials, structures, processes and life over time.
Astronomy - Fantastic images and articles about solar system and deep-space astronomy.
|Ruby and Sapphire
Ruby and Sapphire are the 2nd and 3rd most popular colored stones in the United States.
Volcanic Explosivity - Rating volcanic eruptions based upon the volume of tephra ejected.
||Cave of the Hands
Cave of the Hands is a cave where ancient people painted hands about 9000 years ago.
Troglobites are creatures that have adapted to a permanent life in the darkness of a cave.
Organic Gems are gems formed from or by plants or animals. They might also be fossils.
Tallest Tsunami - A wave with a run-up height of 1720 feet occurred in Lituya Bay, Alaska.
Petrified Wood is a fossil that forms when dissolved material preciptates and replaces wood.
||Lunar Rift System
Lunar Rift System? Gravity maps revise the geologic history of the near side of the moon.
|Rare Earth Elements
Rare Earths - Special materials used in electronics, defense, medical & many other products.
Corundum is the third hardest mineral. It is also the mineral of ruby and sapphire.
||Geologic Time Scale
Divisions of Geologic Time - USGS time scale with unit names and age estimates.
Sand is a diverse material. This gallery includes photos of sand from around the world.
|San Andreas Fault
The San Andreas Fault - A feature that separates the Pacific and North American Plates.
Meteorites - Rocks that were once parts of planets or large asteroids.
||Facts About Copper
Facts About Copper - Information about copper uses, production, resources and more.
Tanzanite was unknown until a few decades ago but it has erupted into wide popularity.
Soapstone is a metamorphic rock with properties that make it suitable for a variety of projects.
Largest Earthquake ever recorded - Magnitude 9.5. Chile, 1960.
Mount Etna - The most active volcano in Europe continues an eruption that started in 2001.
||USA Landslide Map
Landslide Incidence Map - A USGS map showing landslide incidence in the United States.
|What is LNG?
What is LNG? The use of LNG as an energy source is growing rapidly. Learn more about LNG.
Tallest Mountain - Everest has rivals in tallness, altitude and distance to the center of Earth.
||What is a Maar?
What is a Maar? The second most common volcanic landscape feature on Earth.
Iolite is the gem variety of the mineral cordierite. An alternative to sapphire and tanzanite.
Garnet is best known as a red gemstone. It occurs in any color and has many industrial uses.
||Watch out for Ticks!
Ticks are a problem for geologists in some areas. Learn to recognize and avoid them.
Most Powerful Eruption of the 20th Century - One hour later, the blast was heard in Juneau.
Largest Desert - The Sahara is huge but two polar deserts are larger.
|Types Of Eruptions
Types of Volcanic Eruptions - A description of the most common eruption types.
||The Acid Test
The Acid Test - Geologists use dilute hydrochloric acid to identify carbonate minerals.
Ametrine is a bicolor quartz (amethyst + citrine) and a gemstone of growing popularity.
||Uses of Marble
The Uses of Marble are numerous and diverse. You will be surprised by how it is used.
|What Is The Moho?
What Is The Moho? Learn about the Mohorovicic Discontinuity - the mantle/crust boundary.
Horizontal Drilling has opened new resources and significantly improved productivity.
Frac Sand - The amount of frac sand produced in the USA is up by over 300% since 2009.
Mineraloids are amorphous naturally-occurring inorganic solids that lack crystallinity.
|What is a Geyser?
Photos of Geysers from around the world with information about height, eruption interval, more.
The Host Rock of Diamonds - Diamonds are found in Kimberlite, a variety of peridotite.
Pumice is a rock formed during explosive volcanic eruptions. It has a wide variety of uses.
Metals are important mineral products used in manufacturing and construction projects.
Oil Sands contain oil in the form of bitumen. A major oil resource that can be difficult to produce.
||Coal Close Up
Coal Through a Microscope - Coal is more than a black rock. It is THE most interesting rock.
||Great Rift Valley
The East Africa Rift System - The extensive fault system that is tearing Africa apart.
Sunstone is a gem feldspar with aventurescence caused by light reflecting from platy inclusions.
Chatoyant Gems look like the eye of a cat. They have a line of light that moves across the stone.
California Earthquake Maps - A collection of isoseismal maps for earthquakes in California.
Largest Volcano - That title is shared by Tamu Massif, Mauna Kea and Ojos del Salado.
||Eagle Ford Shale
Eagle Ford Shale - One of the most prolific producers of oil and gas in the United States.
|Rocks on Mars
Rocks on Mars - Many of the rocks found on Mars are not very different from Earth rocks.
Methane Hydrate deposits contain more fuel value than all other fossil fuels combined.
Hydraulic Fracturing - Increases well yield by fracturing the reservoir rock with fluid injection.
Salt Glaciers are masses of salt that flow downslope under their own weight.