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About the Author

Hobart M. King, Ph.D., GIA GG

Dr. Hobart M. King

Hobart M. King

Hobart M. King is the manager and publisher of Geology.com. He is a geologist with over 45 years of experience, has a Ph.D. in geology, and is a GIA graduate gemologist. Much of his work has focused on coal geology, industrial minerals, gemology, geologic hazards, and geoscience education.

He has authored many of the internet’s most popular articles about rocks, minerals and gems. He writes most of the content published on Geology.com and compiles its daily news. His writing is read by over a million people each month, making him one of the world’s most widely read geologists.

His education includes: a Ph.D. and an M.S. in geology from West Virginia University; a B.S. in geology from California University of Pennsylvania; and, a Graduate Gemologist Diploma from the Gemological Institute of America. He is a registered professional geologist in the Commonwealth of Pennsylvania.

He has worked as a geologist in a variety of settings since 1975.

West Virginia University
Worked on research projects related to the geochemistry and mineralogy of coal and shale.
West Virginia Geological and Economic Survey
Worked in the positions of coal geologist, economic geologist and Head of the Economic Minerals and Geologic Hazards Section.
Pennsylvania State University
Taught introductory geology as an adjunct professor at the Fayette and McKeesport campuses.
Mansfield University of Pennsylvania
Taught courses in geology, hydrology, global positioning systems, and web-based cartography. Director of the Center for Effective Teaching, content area advisor for the Earth and Space Science Education Program.
Manager, primary author and publisher.

Dr. King was recently featured in an alumni profile published by the Gemological Institute of America and in a success story published on the Google Adsense website.

Some of the articles on Geology.com written by Hobart King appear below. Much of his early work can be found in his Google Scholar profile.

In addition to his work at Geology.com, he is also involved in internet retail as owner and manager of RockTumbler.com and WaterproofPaper.com.

Shale The rock that is quickly transforming the energy industry.
Diamonds from Coal?
Diamonds from Coal
Biggest Misconception Lots of people think that diamonds form from coal. Not True!
Ethiopian Opal
Ethiopian Opal
Ethiopian Opal - The new opal heavyweight that might give Australia a run.
Emerald is the most popular green gemstone in the United States and most of the world.
Quartzite a nonfoliated metamorphic rock composed almost entirely of quartz.
Lapis Lazuli
Lapis Lazuli
Lapis Lazuli - a metamorphic rock and the most popular blue opaque gemstone in history.
Mineral Hardness
Mohs Hardness Test
Mohs Hardness Scale is a set of reference minerals used for classroom hardness testing.
The Brewery Rock ?
Making Beer With Rocks - Do you know which fossiliferous rock is used to make beer?
Tanzanite was unknown until a few decades ago but it has erupted into wide popularity.
The Acid Test
The Acid Test
The Acid Test Geologists use dilute hydrochloric acid to identify carbonate minerals.
Fluorescent Minerals
Fluorescent Minerals
Fluorescent Minerals and rocks glow with spectacular colors under ultraviolet light.
Soapstone is a metamorphic rock with properties that make it suitable for a variety of projects.
Corundum is the third-hardest mineral. It is also the mineral of ruby and sapphire.
Rare Earth Elements
Rare Earth Elements
Rare Earth Elements are used in cell phones, DVDs, batteries, magnets & many other products.
Uses of Gold
Uses of Gold
The Many Uses of Gold Unique properties make gold one of the most useful metals.
Ruby and Sapphire
Ruby and Sapphire
Ruby and Sapphire are the 2nd and 3rd most popular colored stones in the United States.
Topaz is a popular birthstone and the #8 mineral in the Mohs Hardness Scale.
Garnet is best known as a red gemstone. It occurs in any color and has many industrial uses.
Geodes look like ordinary rocks on the outside but can be spectacular inside!
Moldavite is a gem material born about 15 million years ago when a pair of asteroids struck Europe.
Olivine is a rock-forming mineral found in the crust, the mantle, and in some meteorites.
Frac Sand
Frac Sand
Frac Sand The amount of frac sand produced in the USA is up by over 300% since 2009.
Wrong Volcano! The most powerful eruption of the 20th century was misidentified?
Petrified Wood
Petrified Wood
Petrified Wood is a fossil that forms when dissolved material precipitates and replaces wood.
Coal Close Up
Coal Through a Microscope Coal is more than a black rock. It's THE most interesting rock.
Utica Shale
Utica Shale
Utica Shale A giant reservoir of natural gas, oil, and natural gas liquids below the Marcellus.
Salt Domes
Salt Domes
Salt Domes - Salt structures that are often associated with oil and natural gas.
Homeowners Insurance
Homeowners Insurance
Homeowners Insurance usually does not cover the most common geologic hazards.

Articles About Rocks

Amphibolite Marble
Andesite Novaculite
Basalt Obsidian
Breccia Pegmatite
Caliche Peridotite
Chert Pumice
Coal Quartzite
Conglomerate Rhyolite
Diatomite Sandstone
Diorite Schist
Dolomite Scoria
Flint Shale
Gabbro Siltstone
Gneiss Slate
Granite Soapstone
Iron Ore Tuff

Articles About Minerals

Andalusite Ilmenite
Anhydrite Jadeite
Apatite Kyanite
Arsenopyrite Limonite
Augite Magnesite
Azurite Magnetite
Barite Malachite
Bauxite Monazite
Beryl Muscovite
Biotite Nephrite
Bornite Olivine
Calcite Orthoclase
Cassiterite Plagioclase
Chalcopyrite Pyrite
Chlorite Quartz
Chromite Realgar and Orpiment
Chrysoberyl Rhodochrosite
Cinnabar Rhodonite
Copper Scapolite
Cordierite Serpentine
Corundum Silver
Diamond Sodalite
Diopside Sphalerite
Dolomite Spinel
Epidote Spodumene
Feldspar Staurolite
Fluorite Sulfur
Fuchsite Talc
Galena Titanite
Garnet Topaz
Gold Tourmaline
Graphite Turquoise
Gypsum Variscite
Halite Zircon
Hematite Zoisite

Articles About Gemstones

Amethyst Labradorite
Ametrine Lapis Lazuli
Ammolite Maw Sit Sit
Ant Hill Garnet Moldavite
Aventurine Opal
Azurmalachite Peanut Wood
Bloodstone Polka Dot Agate
Brown Diamonds Prasiolite
Chrysoprase Red Beryl
Emerald Rose Quartz
Fancy Sapphire Ruby and Sapphire
Gem Silica Smoky Quartz
Goldstone Strontium Titanate
Helenite Sunstone
Heliodor Tanzanite
Iris Agate Tiffany Stone
Jade Turritella
Jet Unakite
General Geology

Articles About General Geology

Blood Diamonds Hydraulic Fracturing
What is a Caldera? World Lightning Map
Canadian Diamond Mines Liquefied Natural Gas
Crater of Diamonds Marcellus Shale
Crushed Stone Methane Hydrates
Difficult Rocks Mineral Rights
Eagle Ford Shale Mohorovicic Discontinuity
Expansive Soil Oil Sands
Gem Diamond Map Ticks and Lyme Disease
Geysers Titanium
Green River Fossils Trap Rock
Helium Volcanic Ash
Herkimer Diamonds Water Dowsing
Horizontal Drilling  
More General Geology
  Spectacular Fossils
  What is the San Andreas Fault?
  Bubbles in Amber
  Geology Dictionary
  Igneous and Volcanic Features

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Find Other Topics on Geology.com:

Rocks: Galleries of igneous, sedimentary and metamorphic rock photos with descriptions.
Minerals: Information about ore minerals, gem materials and rock-forming minerals.
Volcanoes: Articles about volcanoes, volcanic hazards and eruptions past and present.
Gemstones: Colorful images and articles about diamonds and colored stones.
General Geology
General Geology: Articles about geysers, maars, deltas, rifts, salt domes, water, and much more!
Geology Store
Geology Store: Hammers, field bags, hand lenses, maps, books, hardness picks, gold pans.
Earth Science Records
Earth Science Records: Highest mountain, deepest lake, biggest tsunami and more.
Diamonds: Learn about the properties of diamond, its many uses, and diamond discoveries.