| Earth Science Department
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| Earth Science Department
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I chose to do my web page for GO 336 Mineralogy on the mineral gypsum and its many uses. I wanted to cover how this mineral is relevant to our everyday life. In addition, I also wanted to give an explanation as to why gypsum is so very valuable to the life we have become accustom to.
Table of Contents I. General Gypsum Breakdown II. Physical Characteristics III. Uses of Gypsum IV. Mining of Gypsum V. Overview VI. Sources
General breakdown of the Mineral Gypsum · Chemistry: CaSO4 2H2O, Hydrated Calcium Sulfate · Class: Sulfates · Some common uses: sheetrock (wall board), plaster, cement, fertilizer, paint filler, and ornamental stone.
· Gypsum is a common mineral and is found throughout the world. There are numerous locations within the United States, and North America as a whole. New York, Utah, Colorado, Oklahoma and Mexico are just a few locations where excellent specimens have been found. Gypsum is a common mineral within sedimentary environments. It is a valuable rock forming mineral that is commonly found in massive beds often from precipitation out of highly saline waters. Because of its formation it can and often times does have many inclusions of other minerals and it may even have trapped air bubbles. Selenite, satin spar, and alabaster are a few of the variety names of gypsum. · Selenite is a colorless and transparent variety that can show pearl-like luster, and may have a banded appearance. · Satin spar gypsum has a fibrous appearance, and is often times a milky white or pink color. · Alabaster is a fine grained massive material that is carved into ornaments. [Source #1] Return to table of contents. Physical Characteristics · Color: usually white, colorless or gray, may also be shades of red, brown, and yellow. · Luster: vitreous to pearly especially on cleavage surfaces. · Transparency: may be transparent to translucent. · Crystal System: monoclinic. · Habits: tabular, bladed or blocked crystals. Pinacoid faces may be present. Long thin crystals like those found in satin spar gypsum may show its flexible tenacity with curves. Twinning is also possible. Other habits can include massive, granular, earthy, and fibrous. · Cleavage: good in one direction, and noticeable in two others. · Fracture: rare but if seen will be uneven. · Hardness: low, registers 1.5 to 2 on Moh’s Hardness Scale. · Specific Gravity: 2.3 to 2.4. · Streak: white. [Source #1] Other important information: Some crystals may be flexible. This means that thin bands of the mineral will bend and change shape but will not return to the original form once the pressure is released. This is often seen in the satin spar variety. Gypsum is a poor conductor of heat, which makes it useful in wall board. [Source #1] Return to table of contents. The Uses of Gypsum Gypsum is one of the most widely used minerals in the world. Most is used to make wall board, also know as sheet rock. It is estimated that the average American home contains seven metric tons of gypsum. Gypsum is also added to concrete to strengthen the material, so it can be used in concrete for roads, bridges and sidewalks just to name a few. Gypsum can also be used as a fertilizer by adding it directly to the soil. This increases the productivity of the land. It can be added to paint as a filler. Used in these ways, gypsum must first be ground up into a powder and dried. It is thought that the first uses of gypsum were for sculptures. Alabaster is a soft solid form of gypsum that takes carvings well thus it was able to be carved into many different shaped objects. 5,000 years ago the Egyptians learned to turn the gypsum into what we now call Plaster of Paris, and they used it to line the walls of their living quarters. They discovered that if the gypsum was ground up into a fine powder and dried, that they could later add water, mix and use as cement. [Source #7] The transparent form of gypsum (selenite) was used for windows before glass was created. Gypsum contains a large amount of water, and this gives it fire protection qualities. [Source #7] This is important because it will give some protection from house fires. It is also important because it can be used as molds, allowing melted metals to be poured and formed within. Tiles found in the bathroom are more often than not attached to the wall with a form of gypsum mortar. Plates, cups and saucers from your kitchen were most likely poured into a gypsum formed mold. The uses of gypsum are, as we can see nearly endless. I have only touched on a few, but we can be sure that we will encounter gypsum in some form or another nearly everyday. Return to table of contents. Mining of Gypsum Because gypsum is often found in large thick layers near the Earth's surface, it is easily mined. Once a large bed of gypsum is discovered a mining company will set up shop and begin to extract the mineral from the ground. It may take years before the site is exhausted. Large machines will be used to blast and remove the gypsum, often times destruction to the environment is nearly impossible to control. The importance of gypsum has resulted in a tolerance of this environmental destruction. Once the mining is no longer economically valuable the site is closed. Then, an alternate site is selected, and the mining process starts over. This natural resource is so abundant it is not thought of as in danger of being used up worldwide. However, this may someday be an issue. Gypsum is a recyclable product, but only a small amount is recycled every year because of its abundance. Once the gypsum is mined, it must then be processed. This may consist of grinding the gypsum into a powder, then heating it to remove most of the moisture to allow for transport and to make the transition into a final product. In 2000, gypsum output was more than 25 million tons, and was valued at $175 million. [Source #6] The top producing US states were Oklahoma, California, Iowa, Texas, Nevada, Michigan, and New Mexico. These states accounted for 75% of the total output. The top three gypsum producing countries in 2000 were the United States, Australia, and Canada. [Source #6] Return to table of contents. Overview As you can see gypsum is a valuable mineral that is needed in many aspects of life. Many may argue that gypsum is the single most important mineral to our everyday life. I will not go that far but we must admit that no one could faithfully argue that gypsum in its many forms is not an integral part of life as we know it. Yes, if there was no such mineral as gypsum we would find alternate ways to substitute for this mineral, we have even in some small ways done such. We now have a synthetic form of gypsum that will assist us in the future if and when the gypsum reserves we have come to rely on so heavily have been depleted. The chances that gypsum will be completely mined from the Earth within the next 100 years is virtually impossible, so we should not be consumed with such a threat. We should however recognize the fact that gypsum is very valuable and important, and like all natural resources we should do everything we can to conserve and preserve. Return to table of contents. Sources Source #1 GeoKansas Gypsum, World Wide Web URL: http://www.kgs.ku.edu/Extension/KGSrocks/gypsum_def.html. Retrieved on November 19, 2002. Source #2 Chesterman, C. 1978. The audubon society field guide to north American rocks and minerals. Random House. Source #3 Pellant, C. 1992. Rocks and minerals. Dorling Kindersley, London. Source #4 Klein, C. 2002. Mineral science (22nd ed.). John Wiley & Sons Inc., NY. Web Page Sources Source #5 Mineral Galleries, The Mineral Gypsum, World Wide Web URL: http://mineral.galleries.com/minerals/sulfates/gypsum/gypsum.htm. Retrieved on November 19, 2002. Source #6 USGS Minerals, World Wide Web URL: http://minerals.usgs.gov/minerals/. Retrieved on November 19, 2002. Source #7 http://webmineral.com/data/Gypsum.shtml Source #8 http://webmineral.com/cgi-bin/search/search.pl Source #9 http://archnet.org/library/downloader/document/4554/dpt0496.pdf Source #10 http://www.geo.msu.edu/geo333/gypsummining.html
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Date of creation: 19 November, 2002. Copyright 2002 Jake Bray. I can be reached at jake305@yahoo.com. All rights reserved.