1. Education
Send to a Friend via Email

Your suggestion is on its way!

An email with a link to:

http://geology.about.com/popular.htm

was emailed to:

Thanks for sharing About.com with others!

Geology: Most Popular Articles

These articles are the most popular over the last month.
Identify Almost Any Rock with This Table
Identify 43 of the most common rock types: igneous, sedimentary and metamorphic.
See the Densities of the Most Common Rock Types
Density, or specific gravity, of common rock types.
Use This Master Index of Rock Pictures
My master alphabetical guide to igneous, sedimentary and metamorphic rock pictures.
What to Know About Igneous Rocks
Introducing igneous rocks, first of the three great rock classes (along with sedimentary and metamorphic rocks).
What to Know About Sedimentary Rocks
Introducing sedimentary rocks, second of the three great rock classes (along with igneous and metamorphic rocks).
Why the Earth's Crust Is So Important
The Earth's crust is exceptionally important, and not just because we live on it.
Identify Typical Minerals with This Master...
My master guide to annotated pictures to help you identify minerals: typical examples of rock-forming, accessory, and rare or notable minerals.
What Makes Metamorphic Rocks Special
Most of the thousands of rare minerals known to science occur in metamorphic rocks, which are formed by great heat and pressure. Introducing
The Most Common Green Minerals in Nature
A guide to the most common and significant green and greenish minerals.
What Is Chemical Weathering?
A short explanation of chemical weathering.
10 Steps to Help You Identify Any Mineral
Mineral identification starts with picking a good specimen.
6 Things to Know About the Earth's Mantle
A six-part look at the basics of the Earth's mantle, the part between the crust and the core.
Gabbro
Gabbro is one of the major igneous rock types. Page 7.
Why Granite is the Signature Rock of Earth
Granite is the signature rock of the continents. Here are the basics of this important stone.
Siltstone
Siltstone is one of the major types of sedimentary rocks. Page 24.
Schist
Schist is a major metamorphic rock type from regional metamorphism. Page 15.
Obsidian
Obsidian is one of the major igneous rock types. Page 13.
Granite
Granite is one of the major igneous rock types. Page 8.
Quartzite
Quartzite is a major metamorphic rock type from regional metamorphism. Page 14.
Diorite
Diorite is one of the major igneous rock types. Page 4.
Gneiss
Gneiss is a major metamorphic rock type from regional metamorphism. Page 6.
Metamorphic Rock Types
The major metamorphic rock types, from regional, contact and mechanical metamorphism.
Slate
Slate is a major metamorphic rock type from regional metamorphism. Page 17.
Pumice
Pumice is one of the major igneous rock types. Page 18.
How to Look at a Rock Like a Geologist
Notes on the most basic operation in geology.
Pegmatite
Pegmatite is one of the major igneous rock types. Page 14.
Scoria
Scoria is one of the major igneous rock types. Page 22.
More Than 50 Different Landforms in Pictures
Find and see geological landforms at About.com Geology.
Basalt
Basalt is one of the major igneous rock types. Page 3.
Serpentinite
Serpentinite is a major metamorphic rock type from regional metamorphism. Page 16.
What Is My Blue or Purple Mineral?
A guide to the most common and significant blue and purple minerals.
Fault Types in a Nutshell
The three basic types of fault, with their nomenclature, in a nutshell.
Peridotite
Peridotite is one of the major igneous rock types. Page 15.
Igneous Rock Types
The major igneous rock types, plutonic, intrusive and extrusive.
How to Tell the Feldspar Minerals Apart
Feldspar is the commonest mineral in the Earth's crust, but identifying it can be tricky.
Tonalite
Tonalite is a felsic plutonic rock without alkali feldspar. Page 24.
What Is the Most Common Mineral on Earth?
This question has several answers, depending on what a mineral is and what part of the Earth we're talking about.
Granodiorite
Granodiorite is one of the major igneous rock types. Page 9.
Porphyry
Porphyry is one of the major igneous rock types. Page 17.
Rhyolite
Rhyolite is one of the major igneous rock types. Page 21.
Pyroxenite
Pyroxenite is one of the major igneous rock types. Page 19.
Syenite
Syenite is one of the major igneous rock types. Page 23.
Felsite
Felsite is one of the major igneous rock types. Page 6.
Sedimentary Rock Types
The major types of sedimentary rocks.
Shale
Shale is one of the major types of sedimentary rocks. Page 23.
Phyllite
Phyllite is a major metamorphic rock type from regional metamorphism. Page 13.
Where to Look for Rocks and Minerals
Rocks and minerals can be found everywhere, but there is a learning process involved.
Sandstone: What It Is and What It Tells Us
Sandstone is sand cemented together into rock.
Sandstone
Sandstone is one of the major types of sedimentary rocks. Page 22.
Troctolite
Troctolite is one of the gabbroid rocks: igneous, plutonic and mafic. Page 25.
What a Black Mineral Is Most Likely to Be
A guide to the most common and significant black minerals.
Quartz Monzonite
Quartz monzonite is one of the major igneous rock types. Page 20.
Marble
Marble is a major metamorphic rock type from regional metamorphism. Page 10.
Komatiite
Komatiite is a rare and ancient ultramafic lava. Page 11.
Migmatite
Migmatite is a major metamorphic rock type from regional metamorphism. Page 11.
Dunite
Dunite is a plutonic rock consisting of olivine. Page 5.
Andesite
Andesite is one of the major igneous rock types.
Perlite
Perlite is one of the major igneous rock types. Page 16.
Kimberlite
Kimberlite is the peculiar deep-seated ultramafic rock most famous as the ore of diamonds. Page 10.
Exfoliation
How big rock domes peel off in shells. Page 6.
Chert
Chert is one of the major types of sedimentary rocks. Page 7.
Latite
Latite is the extrusive equivalent of monzonite. Page 12.
Arkose
Arkose is one of the major types of sedimentary rocks. Page 2.
Greenstone
Grenstone is a major metamorphic rock type from regional metamorphism. Page 8.
Coquina
Coquina is one of the major types of sedimentary rocks. Page 11.
Quartz: How to Tell It, Different Kinds, What...
Quartz is essential to the land as we know it.
Tuff
Tuff is one of the major igneous rock types. Page 26.
Anorthosite
Anorthosite is one of the major igneous rock types. Page 2.
Rock Gypsum
Rock gypsum is one of the major types of sedimentary rocks. Page 20.
Graywacke or Wacke
Wacke or graywacke is one of the major types of sedimentary rocks. Page 15.
How to Use the Mohs Hardness Scale to Identify...
The 10-mineral Mohs scale of relative hardness is based on what scratches what.
Limestone
Limestone is one of the major types of sedimentary rocks. Page 17.
Travertine
Travertine is one of the major types of sedimentary rocks. Page 25.
Conglomerate
Conglomerate is one of the major types of sedimentary rocks. Page 10.
Fossil Picture Gallery
Pictures of fossils, part of the About.com Geology gallery of images.
The Size Divisions of Sediment Particles
The grain sizes of sediments and sedimentary rocks are a matter of great interest to geologists. Here is a guide to sediment grades and grain sizes.
Mechanical Weathering
A short explanation of mechanical weathering.
Where Are the Greatest Earthquake Threats in...
The United Nations' global map of seismic hazard
What Is My Red or Pink Mineral?
A guide to the most common and significant red and pink minerals.
Rock Salt
Rock salt is one of the major types of sedimentary rocks. Page 21.
Mylonite
Mylonite is a major metamorphic rock type from mechanical metamorphism. Page 12.
Breccia
Breccia is one of the major types of sedimentary rocks. Page 6.
Peat
Peat is one of the major types of sedimentary rocks. Page 18.
Claystone
Claystone is a type of sedimentary rock. Page 8.
Hornfels
Hornfels is a major metamorphic rock type from contact metamorphism. Page 9.
Silica Tetrahedron Defined and Explained
The silica tetrahedron is the basis of the silicate minerals.
Dolomite Rock or Dolostone
Dolomite or dolostone is one of the major types of sedimentary rocks. Page 14.
Soapstone
Soapstone is a major metamorphic rock type from regional metamorphism. Page 18.
Minerals with Metallic Luster
Minerals with metallic luster are easy to learn to identify.
Diamictite
Diamictite is a messy rock that is not quite conglomerate. Page 12.
The Scientific Definition of a Mineral
Minerals meet four criteria, more or less strict.
Translate Names Between Gemstones and Minerals
Big list of mineral names and their corresponding gemstone names.
Greenschist
Greenschist is a major metamorphic rock type from regional metamorphism. Page 7.
Quartz
Quartz is classified as a rock-forming mineral. Page 9.
Ironstone
Several types of sedimentary rocks are called ironstone. Page 16.
Diatomite
Picture and notes about the sedimentary rock diatomite. Page 13.
Florida Geologic Map
Geologic map of Florida, part of a set of all 50 states. Page 9.
Viewing Earth from on High
Satellite views of Earth's surface make possible geological discoveries never before imagined.
Coal
Coal is one of the major types of sedimentary rocks. Page 9.
North Carolina Geologic Map
Geologic map of North Carolina, part of a set of all 50 states. Page 33.
Banded Iron Formation
Banded iron formation or BIF is one of the major types of sedimentary rocks. Page 4.
Mineral Pictures A to Z
A-to-Z list of minerals shown on About.com Geology.
What to Know Before You Buy a Magnifier
What to think about and look for when you set out to get a nice magnifier.
About Subduction in Plate Tectonics
Basics of plate tectonics: introduction to subduction.
The Bowen Reaction Series
About this staple of igneous petrology.
Porcellanite
Porcellanite is a subtle sedimentary rock type. Page 19.
Sizes of Tectonic or Lithospheric Plates
Table listing the lithosphere's tectonic plates by oder of size.
Plutonic Rocks
Plutonic rocks defined and explained.
Eclogite
Eclogite is a major metamorphic rock type from regional metamorphism. Page 5.
Bauxite
Bauxite is an uncommon but economically important sedimentary rock. Page 5.
The Lithosphere in a Nutshell
What you need to know about the lithosphere.
Geologic Maps of the 50 United States
Geologic maps of all 50 U.S. states.
Argillite
A lightly metamorphosed claystone also called pipestone. Page 2.
Texas Geologic Map
Geologic map of Texas, part of a set of all 50 states. Page 43.
Georgia Geologic Map
Geologic map of Georgia, part of a set of all 50 states. Page 10.
Volcanic (Extrusive) Rock Types
Photos of the types of erupted igneous rocks.
Natural Asphalt
Natural asphalt is one of the major types of sedimentary rocks. Page 3.
Blueschist
Blueschist is a major metamorphic rock type from regional metamorphism. Page 3.
Gallery of Concretions
Concretions are cemented bodies of sediment that tend to erode free.
Actinolite
Actinolite is a major amphibole mineral. Page 5.
Amphibolite
Amphibolite is one of the major metamorphic rock types.
What Is My Yellow Mineral?
A guide to the most common and significant yellow minerals.
Rock Cycle Diagram
The rock cycle as I see it. Geology.
What You Should Know About the San Andreas Fault
Home page for everything about the San Andreas fault: where it is, how it behaves, what it means.
About Transforms - Plate Tectonic Transform...
Basics of plate tectonics: what happens when plates move past each other.
Outcrops versus Exposures, an Essay
When is an exposure really an outcrop, or vice versa?
California Geologic Map
Geologic map of California, part of a set of all 50 states. Page 5.
About Convergent Zones in Plate Tectonics
Basics of plate tectonics: convergent zones are where plates come together.
Measuring Plate Motion
The five ways we track the motion of the lithospheric plates.
Steno Started Geology with a Few Simple...
Steno (Niels Stensen) first set forth some of the basic principles that all geologists follow.
What Counts as a Rock to a Geologist?
Everyone knows what a rock is, until you ask what it is exactly.
North Dakota Geologic Map
Geologic map of North Dakota, part of a set of all 50 states. Page 34.
Erosion: Introduction to This Central Concept...
A short explanation of erosion. Geology.
What You Should Know about the Earth's Core
The whole Earth on average consists of the same mixture of stuff we see elsewhere in the solar system, but the core has to be iron metal along with some nickel.
The Rock-Forming Minerals
A handful of very abundant minerals account for the great majority of the Earth's rocks.
Plate Tectonics Explains How the Earth's...
Start here to learn the basics of plate tectonics.
Alabaster
Alabaster or massive gypsum rock is one of the sedimentary rocks.
Cataclasite
Cataclasite is a major metamorphic rock type from mechanical metamorphism. Page 4.
Olivine
Olivine is an important rock-forming mineral. Page 7.
Gallery of Mineral Lusters
Gallery of this key attribute of minerals.
Pyroxene (Augite)
Pyroxene is a rock-forming mineral. Page 8.
Actinolite, Northern California
Actinolite in the gallery of amphibole minerals. Page 6.
Potassium-Argon Dating Methods
Potassium-argon isotopic dating is especially useful for determining the age of lavas.
Quartz and Silica Minerals Gallery
Get familiar with quartz.
Earthquakes - The Basics in a Nutshell
Start here for the seismic basics: faults that cause earthquakes, types of seismic waves, damages they cause and more.
Agate
Agate is a rock made of chalcedony or cryptocrystalline quartz. Page 14.
QAP Diagram for Plutonic Rocks
QAP ternary diagram showing IUGS classification of phaneritic igneous rocks.
Fast Links for Real-Time Info on Current...
Directions to information and data from earthquakes as fast as possible.
Actinolite Closeup
Closeup of actinolite in the gallery of amphibole minerals. Page 7.
Map of Plates and Their Boundaries
Details of the world's major tectonic plates and their boundaries.

©2014 About.com. All rights reserved.