Talk:Calcite

Calcite dose not have a conchoidal fracture it is a rhombohedral fracture. — Preceding unsigned comment added by 2600:1702:390:1C40:847A:2EC4:EFF2:65BF (talk) 18:50, 19 February 2023 (UTC)

Comments

OK - removed the following from article and formatted for readability. There is useable info here, but needs considerable work to avoid duplication, etc.

Main.html

Calcite is one of the most important and abundant minerals on Earth. The varieties of calcite are unlimited and they serve numerous purposes, from decorations to common household and building materials to nature’s most exquisite sightings. Amazingly, calcite takes up about 4% of the weight of Earth’s crust! Calcite is both beautiful and inexpensive, making it wonderful for gifts or decoration. This mineral has been mined for years, and it has proved itself worthy of years of mining in the future.

Chem.html

Calcite, CaCO₃(Calcium Carbon and three Oxygen atoms),is a very common mineral that forms in many different ways and has a good source of calcium carbonate. There are around 300 types of calcite. Two common ones are Dogtooth Spar and Iceland Spar. Calcite usually colorless to white, but it can be gray, red, yellow, orange, blue, green, purple, pink, brown, or black, and has a white streak. Impurities often change the color. For example, if calcite has a small amount of nickel, a greenish color is taken on. A slight amount of magnese makes a pink color, while iron makes a brown color. The luster, which is the way the mineral, reflects light, is pearly, or vitreous. The density, or specific gravity, is 2.7 cm³/g. The hardness is three by the Moh’s scale of hardness. Formed in the way similar to stalagmites and stalactites with water dripping, there are many crystal formations of calcite. It can be in the crystal system of trigonal in the class of hexagonal scalenohedral. This type of crystal system is 3-D <http://www.webmineral.com/crystal/Trigonal-HexagonalScalenohedral.shtml>

This crystal formation has three 2-fold rotation on its axis, which is the vertical line. This means that you can turn the crystal 180º (binary symmetry) and it would look the same. It also has one 3-fold rotation, which means that you can turn the crystal 120º (trigonal symmetry) and it would look the same. Another type of formation that calcite forms as is orthorhombic-dipyramid (double pyramid). This crystal looks like this: http://www.webmineral.com/crystal/Orthorhombic-Dipyramidal.shtml

This crystal formation has three 2-fold rotation, too. The axes are unequal in length and the axes are all in 90º angles. Other crystal formation include rhombohedral, triclinic pinacoidal, and monoclinic prismatic. http://www.webmineral.com/crystall.shtml has explanations and other links explaining these formations. A pure calcite crystal is rhomobohedrons, but those are extremely rare.

Calcite has perfect cleavage 75º in three directions and conchoidal fracture. Conchoidal fracture is shell shaped, but this is rare because of the cleavage. The tenacity is brittle.

Calcite has several unique properties. It can polarize light, has fluorescence, phosphorescence, thermoluminescence, triboluminescence, double refraction, and fizzes with a weak acid, such as hydrochloric acid (diluted) or vinegar. Polarized light is light that has been “filtered”. : Unpolarized light has light waves that vibrate in all different directions. When the unpolarized light goes through calcite, calcite blocks out light waves that don’t go in a certain direction, so the light that is shone out has light waves that all go in the same direction. Fluorescence is the property that some minerals have when ultra-violet light is shined onto the mineral and it glows. Phosphorescence comes right after; it is the property that some minerals have where the mineral continues to glow, even after the ultra-violet light is taken away. Thermoluminescence is the property where after the glowing has ceased, you can make it glow again by heating it up. Triboluminescence is where the mineral can glow by friction. Double refraction is the property where if you put a mineral, in this case calcite, on a sentence of a magazine and look through it, you see two images of the same thing.

Calcite is a complex mineral with brilliant looks and many identifying and useful properties.

Uses.html

Calcite is found in many materials but the most common places are marble and limestone. Limestone is used in cement and mortar and building stones. Limestone can also be found in fertilizer and ornamental stones. Calcite can also be found in some alabaster and chalk. It is also used in scouring and cleaning powders because of its softness. Iceland Spar was used in World War II as optical equipment. Calcite is also used in special lenses, such as the ones in a dichroscope, which shows pleochroric colors, which are the different colors some minerals show when you view them from different angle or axes, of some gems or minerals. Calcite is also found in exo-skeletons of some invertebrates. Shells and coral consisting of calcite were found on beaches in Florida and the along the Gulf of Mexico. Calcite is an important part of Earth’s natural aspects. Soda straws, stalagmites, stalactites, and other cave formations comprise mostly of calcite. Calcite is an amazing mineral, serving so many purposes, and

Localities.html

Calcite is usually found in hydrothermal veins, which are veins that are formed by hot water flowing through cracks in Earth’s crust and taking minerals with it. It makes oolitic rocks, which is a type of sedimentary rock, and fossiliferous rocks, which are rocks that have fossils in them. They are common, too, in limestone caves. Calcite is mined annually in many places worldwide. Some major areas for calcite mining are Eskifjord in Iceland, where Iceland Spar was found and named after, Colbalt, Timiskaming Country, Dungannon Township, Hosting Country, and Ontario all in Canada, the Mount Lofty Ranges in Southern Australia, Cochise County in Arizona, Franklin in New Jersey, Egremont in the United Kingdom, West Cumbria, and Leadhills in Strathclyde. Calcite is usually obtained from limestone caves. They form in low temperature and can be damaged slightly by the weather. If it rains, the acid in the rainwater will dissolve some of the calcite, so calcite left in the open might be uneven or holey.

Other.html How is calcite similar and different to aragonite? Vaterite?

Calcite and aragonite have the same chemical compositions, calcium carbonate. However, there are some major differences. The structures of the molecules of these two minerals are different. Calcite is usually trigonal, although it can appear in other forms, while aragonite is orthorhombic. Aragonite is harder than calcite and has a higher density. : Aragonite is also more soluble than calcite. Calcite is a stable mineral, meaning it keeps its form, whereas many aragonite minerals change into calcite overtime, making them polymorphs of each other. Calcite and aragonite are in the carbonate family (calcium carbonate) along with dolomite and azurite.

Vaterite also has the chemical formula CaCo. It is also a polymorph to calcite, as well as aragonite. It is even more soluble than calcite and aragonite. When vaterite reacts with water at low temperature, it turns into calcite, and when it reacts with water at high temperature of 60º C or above, it transforms into aragonite. Vaterite does not have the variety of colors as calcite does either; it usually forms in a white color. It doesn’t form in limestone caves, but in mineral springs, which are springs that are rich in minerals.

Conclustion.html

Cites.html

Barthelmy, David. “Crystallography.” Mineralogy Database. May 7 2005. Webmineral. December 7 2005. < http://www.webmineral.com/crystall.shtml >

Bell, Pat and David Wright. Rocks and Minerals. New York: Collier Books, 1985.

Bish, David L. “ Calcite.” World Book Encyclopedia. 2004 ed.

“Calcite.” Diamonds and Gemstones. Edelstein Vertrico Frank Breining. December 6 2005. <http://www.breinling.de/nitrades/calcite.htm >

"Calcite," Microsoft® Encarta® Online Encyclopedia 2005 <http://encarta.msn.com/encyclopedia_761573488/Calcite.html>

Hedegaard, Claus. “Aragonite.” December 8, 2005. <http://www.hedegaard.com/Minerals/Species/Aragonite.html >

Howard, Mike and Darcy Howard. “Part 1: Introduction.” Introduction to Crystallography and Mineral Crystal Systems. 1997-1998. Bob’s rock shop. December 8 2005. <http://rockhounds.com/rockshop/xtal/part1.html >

Oldershaw, Cally. Guide to Gems. Buffalo, New York: Firefly Books Ltd., 2003.

Ralph, Jolyon. “Calcite.” The mineral database. December 4 2005. Mindat.org. December 7 2005. <http://www.mindat.org/min-859.html >

Thompson, Brian J. “Polarized light.” World Book Encyclopedia. 2004 ed.

“Vaterite.” Wikipedia.org. July 12 2005. Wikipedia. December 10 2005. <http://en.wikipedia.org/wiki/Vaterite >

I plan to work through this and incorporate parts into the article as appropriate. It was unuseable and unreadable in the unformatted addition. - Later, no time now Vsmith 18:03, 11 December 2005 (UTC)

Gallery?

Is a gallery relevant in an encyclopedia article? Shouldn't pictures only be used where relevant? In my opinion, the gallery section is not needed. Slartibartfast1992 00:56, 5 June 2007 (UTC)

What kind of newbies are you talking about? Newbies on calcite? A couple of pictures well distributed on the article should do the trick. The gallery makes it look like a sort of calcite catalog. This is an encyclopedia, not a way of making people see how "pretty" calcite is or such things. The pictures in the gallery are unnecessary and, therefore, the gallery is too. Because of this I shall redo my edit. Please express any other opinions on the subject here. That's what talk pages are for. Slartibartfast1992 00:49, 15 June 2007 (UTC)

the value for extraordinary and ordinary variation is wrongly read and interchanged in the text. please read the reference 5 carefully, the author has interchanged the tags. actually the upper tag is for lower graph and lower tag is for upper graph —Preceding unsigned comment added by 210.212.158.131 (talk) 10:49, 3 June 2008 (UTC)

Black calcite

Would it be of interest to cite a documented occurence of Black Calcite (carbon pseudomorph) from central Oman? It was written up in the Journal of Mineralogy.James C. Laver (talk) 17:32, 6 February 2009 (UTC)

Carbon pseudomorph or carbon inclusions? Don't have the source. Add it if notable (with full citation of course). Vsmith (talk) 19:43, 6 February 2009 (UTC)

GORDON STANGER JAMES LAVER COLIN NEAL. Black carbonaceous calcite associated with serpentinite from Oman. MINERALOGICAL MAGAZINE, JUNE 1988, VOL. 52, PP. 403 8 http://www.minersoc.org/pages/Archive-MM/Volume_52/52-366-403.pdf

Chalk?

Would it not be important to mention that chalk, a very economically important substance, is fundamentally calcite? Also, antacids such as Tums. 24.240.32.64 (talk) 07:49, 28 August 2013 (UTC)

Calcite formation processes

The formation of calcite is a very hotly debated topic that is complicated by the fact that it forms through various mechanisms depending on the experimental conditions. The existing section is extremely misleading in that it presents only one account (which is not even widely accepted yet). I invite someone with the time and inclination to rewrite this section. — Preceding unsigned comment added by RDWD (talk • contribs) 09:05, 21 October 2014 (UTC)

Final link

I've just clicked on the final link in the body of the article and it doesn't seem to go anywhere. I don't have time to see whether it's badly formed or broken. --TammyMoet (talk) 15:18, 8 December 2014 (UTC)

It was broken, however the galleries.com calcite page info is not an improvement and the page is full o spam - so chopped. Vsmith (talk) 15:30, 8 December 2014 (UTC)

Featured picture scheduled for POTD

Hello! This is to let editors know that File:Fluorescence in calcite.jpg, a featured picture used in this article, has been selected as the English Wikipedia's picture of the day (POTD) for April 29, 2022. A preview of the POTD is displayed below and can be edited at Template:POTD/2022-04-29. For the greater benefit of readers, any potential improvements or maintenance that could benefit the quality of this article should be done before its scheduled appearance on the Main Page. If you have any concerns, please place a message at Wikipedia talk:Picture of the day. Thank you! Cwmhiraeth (talk) 10:50, 21 April 2022 (UTC)

Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO₃). This photograph shows fluorescence and birefringence in a calcite crystal with a 445-nanometre laser.

Photograph credit: Jan Pavelka

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Wiki Education assignment: ERTH 4303 Resources of the Earth

This article was the subject of a Wiki Education Foundation-supported course assignment, between 13 January 2023 and 15 April 2023. Further details are available on the course page. Student editor(s): JaneYin (article contribs). Peer reviewers: Ol Evene, Yibofeng3.

— Assignment last updated by ChloejWard (talk) 03:40, 15 April 2023 (UTC)

Pakistan

I bought a Pistachio Calcite also known as Green Calcite which is mined in Pakistan. And I also bought a Caribbean Calcite which is also mined in Pakistan. Catfurball (talk) 20:46, 3 April 2023 (UTC)