McAfee SECURE sites help keep you safe from identity theft, credit card fraud, spyware, spam, viruses and online scams

Home » Minerals » Gypsum

Gypsum


An important construction material that has been used for thousands of years



What is Gypsum?



Gypsum is an evaporite mineral most commonly found in layered sedimentary deposits in association with halite, anhydrite, sulfur, calcite and dolomite. Gypsum (CaSO4.2H2O) is very similar to Anhydrite (CaSO4). The chemical difference is that gypsum contains two waters and anhydrite is without water. Gypsum is the most common sulfate mineral.


Physical Properties of Gypsum

Chemical Classification sulfate
Color clear, colorless, white, gray, yellow, red, brown
Streak white
Luster vitreous, silky, sugary
Diaphaneity transparent to translucent
Cleavage perfect
Mohs Hardness 2
Specific Gravity 2.3
Diagnostic Properties cleavage, specific gravity, low hardness
Chemical Composition hydrous calcium sulfate, CaSO4.2H2O
Crystal System monoclinic
Uses Use to manufacture dry wall, plaster, joint compound. An agricultural soil treatment.


Uses of Gypsum?



Gypsum uses include: manufacture of wallboard, cement, plaster of Paris, soil conditioning, a hardening retarder in Portland cement. Varieties of gypsum known as "satin spar" and "alabaster" are used for a variety of ornamental purposes, however their low hardness limits their durability.


Gypsum from Michigan
Gypsum from Grand Rapids, Michigan. Specimen is approximately 4 inches (10 centimeters) across.


Gypsum from virginia
Gypsum from North Holston, Virginia. Specimen is approximately 1-1/2 inches (3.8 centimeters) across.


Satin spar Gypsum
Satin spar, a fibrous variety of gypsum from Derbyshire, England. Specimen is approximately 3 inches (7.6 centimeters) across.


Alabaster Gypsum
Alabaster, a variety of gypsum, from Pomaia, Italy. Specimen is approximately 3 inches (7.6 centimeters) across.


Gypsum translucency
The translucent characteristic of alabaster, a variety of gypsum, from Pomaia, Italy. Specimen is approximately 3 inches (7.6 centimeters) across.



Find it on Geology.com




More from Geology.com


Fire Opal
Fire Opal is a transparent to translucent opal with a yellow, orange or red background color.
Green River Formation
The Green River Formation is one of the most famous rock units in the world for its fossils.
Olivine
Olivine is a rock-forming mineral found in the crust, the mantle, and in some meteorites.
Diamonds from Coal
Biggest Misconception: Lots of people think that diamonds form from coal. Not True!
Frac Sand
Frac Sand: The amount of frac sand produced in the USA is up by over 300% since 2009.
caldera
Calderas are enormous volcanic craters formed by some of Earth\'s largest eruptions.
Dallol Volcano
Strange Volcanic Landscape! Photos of Dallol Volcano - an explosion crater in Ethiopia.
Crater of Diamonds
You Can Be A Diamond Miner! At the Crater of Diamonds Mine you keep what you find.


 Gypsum
Satin spar, a fibrous variety of gypsum from Derbyshire, England. Specimen is approximately 4 inches (10 centimeters) across.




gypsum wallboard and plaster
Wallboard and construction plaster are the primary industrial uses of gypsum in the United States.Photo © George Peters and iStockphoto.


Alabaster gypsum jar
Jar made of beautiful translucent alabaster gypsum by David MacFarlane, photo © David MacFarlane and iStockphoto.


Selenite Gypsum
Selenite, a variety of gypsum from Penfield, New York. Specimen is approximately 2-1/2 inches (6.4 centimeters) across.


Gypsum from New York
Selenite, a variety of gypsum from Penfield, New York. Specimen is approximately 2-1/2 inches (6.4 centimeters) across.


More Minerals
  Minerals
  Fluorescent Minerals
  Find Minerals and Gems
  Mineral Identification Chart
  Mohs Hardness Scale
  Gold
  Kyanite
  Quartz




© 2005-2014 Geology.com. All Rights Reserved.
Images, code and content of this website are property of Geology.com. Use without permission is prohibited. Pages on this site are protected by Copyscape.