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Roger Weller, geology instructor

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Calcite
by Rafael Aponte
Physical Geology
Fall 2017
  
 
                                                                              

Calcite, The Mineral With The Most
 

            Calcite is in fact, a carbonate mineral and the most stable polymorph of calcium carbonate as well as being in a hardness of 3 is nothing when rubbed with something harder like a corundum or even a piece of apatite. In a few places in the world, calcite can sometimes get mixed with peoples drinking water causing ill-effects in the body. A problem that affects people in desert areas like Arizona or California, and is an issue when it comes to housing and health. There are ways to know what is Calcite as a mineral, what are the effects when calcite is dissolved/mix in water to other materials, and how calcite is formed in the sinks and what causes it. Showing these might give people an idea of the subject matter at hand to give a few people to make good choices with drinking water in the desert communities. 
 

            The very first question that people have about calcite is “what is it”, well surprisingly this will be a rundown of Calcite as a mineral and its uses. Calcite is a rock-forming mineral with a chemical formula of CaCO3 (Calcium + Carbon +Trioxide), it is also an extremely common mineral found throughout the world in sedimentary, metamorphic, and igneous rocks. Some geologists consider it to be a "ubiquitous mineral" - one that is found everywhere (King), Calcite is a component inside such material as limestone and marble, extremely common rocks that can be found anywhere in the world (even in a desert). Calcite is also used in a wide range of architectural and agricultural jobs its used for (King), for example, calcite can be used in a form of foundation for many buildings that want to appear very pleasing to the eye. The construction industry is the primary consumer of calcite in the form of limestone and marble. These rocks have been used as dimension stones and in mortar for thousands of years. Limestone blocks were the primary construction material used in many of the pyramids of Egypt and Latin America. Today, limestone and marble are still an important material that is used in prestige architecture such as government buildings and if optional, hotels and casinos too (King).

 Calcite also has numerous uses as to neutralize any acids. For hundreds of years, limestones and marbles have been crushed and spread on fields as an acid-neutralizing soil treatment, they are also heated to produce lime that has a much faster reaction rate in the soil (King). Calcite is used as an acid neutralizer in areas were streams are plagued with acid mine drainage, crushed limestone is dispensed into the streams to neutralize their waters. High-grade optical calcite was used in World War II for gun sights, specifically in bomb sights and anti-aircraft weaponry (Lister).  There are many uses when it comes to this commonly found mineral in many places in the world.  








 

            Calcite is not the strongest mineral in the world if others know by now that calcite is in the 3rd mark of the Mohs scale of hardness when exposed to factors of natural and unnatural occurrences that might be a factor in the chemical change of calcite. Water by far is the first the first thing a person might think of when dissolving something like salt or limestone (but it takes a long time to do so), one example of a calcite with another chemical is  one study of mixing Zn2 with calcite and two other substances, in addition to mixtures of calcite with the two other materials,  was investigated at various loadings and mixture compositions using atomic absorption spectroscopy, scanning electron microscopy/energy dispersive X-ray spectroscopy, X-ray powder diffraction, and Fourier transform infrared techniques (Shahwan). Coming back to the subject of water, Calcite can be either dissolved by groundwater or precipitated by groundwater, depending on several factors like if the temperature of the water is high enough , the ph of a certain thing in concentration, and even dissolved ion concentrations. Although calcite is insoluble in cold water, acidity can cause dissolution of calcite and release of carbon dioxide gas. Calcite may be in a way not as strong to withstand acids, but still has its uses for many things, even when it can't up against lemon juice (or something like that).
 

            When a person looks at a sink, what do they see, that white residue that resides around from faucet to the sink, that’s the hardware aka lime (not the fruit the mineral that’s made mostly out of minerals) that was built up when water is used, and this is the reason this minor event starts. The starting point for knowing this stuff is its name, limewater (also known as hard water when dried) is a clear and colorless liquid substance, with a slight earthy smell and an alkaline bitter taste of calcium hydroxide (Seidell and Nostrand).  This mixture is formed when groundwater dissolves carbon dioxides aka CO2 and other material then mixes to become limewater, calcite, surprisingly actually helps with water being manageable by alkalizing the water which offsets the acidity (low pH) of water caused by dissolved carbon dioxide (Calcite Neutralization). Carbon dioxide in small amounts is present in all-natural waters. In reverse osmosis membranes remove the alkalinity present in water but not the carbon dioxide, because it is a gas. This creates a low pH in the product water meaning that the calcite controls the effects of CO2 (Calcite Neutralization). Once again, calcite has more uses than its credited for  overall and makes the water people use safely to consume and bath in.  
 

            In conclusion, calcite is a common mineral that has many properties and applications that are of great use for many people as well as being common among other minerals that exist on this planet. Calcite is a great mineral when it comes to making buildings and makes medicine for some forms of illness that they help to ease it.  Calcite can be dissolved in many forms of reactions and/or acids when it's under the right conditions. The mineral is useful when it comes to regulating other things in the water to balance thing out. Calcite is a material that is very abundant of and has used in many ways for those who know what the properties are and how they apply to  peoples lives. 


 

 

Work Cited

A. Seidell, W. F., Nostrand, Linke, Van. ´Solubility of Inorganic and Metalorganic Compounds - A Compilation of Solubility Data from the Periodical Literature´,(Publisher), 1953

“Calcite Neutralization Filters Information.” Calcite/Neutralization, www.watertreatmentguide.com/calcite_neutralization.htm.

King, Hobart. “Calcite.” Geology.com, Geology.com, geology.com/minerals/calcite.shtml.

Lister, Priscilla. “Borrego's calcite mine trail holds desert wonders.” Sandiegouniontribune.com, 5 Dec. 2010, www.sandiegouniontribune.com/sdut-borregos-calcite-mine-trail-holds-desert-wonders-2010dec05-htmlstory.html.

Shahwan, T., et al. "AAS, XRPD, SEM/EDS, and FTIR Characterization of Zn2+ Retention by Calcite, Calcite-Kaolinite, and Calcite-Clinoptilolite Minerals." Journal of colloid and interface science 286.2 (2005): 471-8. ProQuest. Web. 19 Nov. 2017.