Talk:Clay

Wiki Education Foundation-supported course assignment

This article was the subject of a Wiki Education Foundation-supported course assignment, between 7 January 2019 and 9 April 2019. Further details are available on the course page. Student editor(s): HannahWV. Peer reviewers: Yunxin Song.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 17:48, 16 January 2022 (UTC)

Identification section

This section is frankly terrible and I'd suggest simply deleting it, it's hard to even tell what it's supposed to be about. Is it about identifying if something is a clay or identifying the particular mineral composition? — Preceding unsigned comment added by AngryZinogre (talk • contribs) 04:57, 8 October 2018 (UTC)

I agree that this section needs work, however I would not suggest deleting it altogether. Perhaps it would be worthwhile to change the name to "characteristics of clay" and break it down into physical and chemical properties. Physical properties such as grain size are discussed previously in the article and could be expanded on here, and chemical properties such as ion exchange are not discussed at all, but are important to add. --HannahWV (talk) 22:45, 31 January 2019 (UTC)

why is clay slippery

I think I read that clay is slippery as a result of aluminum hydroxide gels like those described at wikipedia yet theres also a colloidal goop explanation.

Old text

I am not good at editing the main page stuff. But though i should add that Montmorillonite clay is the most common member of the smectite clay family. Montmorillonite is generally referred to as “nanoclay”. It is also the most common material used in plastic nanocomposites. Nanoclay: a clay from the smectite family. Smectites have a unique morphology, featuring one dimension in the nanometer range. Think of them like a deck of cards. They are relatively long and wide compared to their height. If you were to spread them out equally three dimensionally you have reached optimization for most uses. While looking at the spaced out cards one dimension makes them almost impossible to see, yet their effects are extreme. It is currently being use by many companies for various uses. Example companies are Bayer AG, Nanocor, PolyOne, Honeywell, Mitsubishi Gas Chemical, etc. Everyone keeps hearing about nanotechnology, especially about carbon nano-tubes. Nanoclays have made just as much of an impact already but dont have the following.

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Text which was added by anonymous user User:68.120.90.223 should be either removed or modified heavily. It definitely has something which is worth keeping but it also contains childish nonsenses like "clay is soil found in water" etc. This article should begin with geological explanation/definition and it is not what clay is technically, it is what clay actually is. Siim 19:34, 23 November 2005 (UTC)

Message from Professor Tropf of Cal State Northridge

The Wikipedia Help Desk has received a message from Professor Tropf of Cal State Northbridge. Apparently, he tried to rewrite the article to include the use of clay in art. I quote from his e-mail: I tried to amend the article with a paragraph on the use of clay as an artistic medium, but it was removed.

Why was my plain-language addition to a highly technical article removed? How can I write a plain-language explanation of what "clay" is and have it posted on Wikipedia?

I suspect that he was the anonymous user referred to above.

I will seek further information from him and see if we can we develop a compromise. Capitalistroadster 04:17, 25 November 2005 (UTC)

I re-inserted the edit mentioned as a start for a new subsection. The info is good, with some tweaks. I was previously pondering how to make it fit when another editor removed it. The added section probably needs some tuning for better flow. Vsmith 04:53, 25 November 2005 (UTC)

Professor Tropf has e-mailed that he has edited the article which currently appears as the introduction. His text is:

"Clay is a generic name for a number of different types of soils found in or near water. Clay is denser and heavier than most other types of earth. Naturally high in water content, clay is malleable and can be easily shaped by the hands. When dried in the sun it becomes harder, but sun-dried clay will break or crumble over time. Clay can be hardened permanently by heating it in a special oven called a “kiln,” which provides more intense heat, even temperature and faster drying time. The process of hardening clay in a kiln is called “firing.” Clay is found in a variety of colors from gray to reddish orange, but during or after the firing process a clay object can be painted or glazed."

Capitalistroadster 17:11, 25 November 2005 (UTC)

The good prof. needs to read the article, the info is already there - as I mentioned above. Vsmith 17:21, 25 November 2005 (UTC)

I'd like to say "thank you" to the editors of wikipedia and V. Smith, who have helped me create a much better article on the subject of clay. I ask my freshmen-level students to select a work of art and write a research paper on how that artwork was created. Those who choose a ceramic artwork have had a very difficult time finding information on clay as an artistic medium. The original wikipedia article was full of highly technical terms, with no common language explanation for beginners. Now we have an article that can be understood by an undergraduate student with no experience in science, but still includes informaton for advanced scholars.

Ralph Tropf, MFA
Cal State Northridge

Thanks, we may have some misunderstandings, but we try :-). My apologies for the confusion. I have moved your note to the bottom of the page as is the custom for Wikipedia talk pages, new comments at the end. Your edit improved the article - feel free to edit more (that's what it's all about), your expertise is welcome. If you have questions or concerns just ask on the relevant talk page - or ask on my talk page. Vsmith 00:45, 27 November 2005 (UTC)

Firing?

Can someone explain what happens to clay as it is fired? I suspect the silicate drys out, then welds to itself, but that seems like it would only happen in a narrow temperature range (lest the piece melt). Any ideas> —BenFrantzDale 13:20, 20 December 2005 (UTC)

On the principle of "better late than never", see sintering.--Slashme 13:01, 26 September 2007 (UTC)

clay in solution

Okay, so I have a question and an idea. How did people, and how do people, make high quality pure clay for firing in a kiln from clay that probably has silt, sand and organic matter in it?

Well, I have an idea. In soils we learned that clay particles will remain in suspension after two hours, at which time the silt and sand will have dropped out. So assuming that usable firing clay needs only have silt and sand removed, one could get a canister of muddy water, let it sit for two hours and then siphon off as much water as possible without disturbing the silt and sand at the bottom. Then that water, once evaporated, would yeild very nearly 100% clay, right? I just don't know if 100% clay is what the "clay" we used in grade school to make ash trays is.

Also, should this neat little link on making clay to paint with be on the external links on the main page? I'm ages five and up... http://americanhistory.si.edu/kids/santos/TryItWaterBasedPaints.html

Clay will precipitate from a suspension made with hot water, too, after I freeze it. I wonder what's left in solution? As in, would that "filtrate of freezing" support an algae bloom if I seeded it with a Tsp. from my aquarium. Calcium and Silicate are major components of clay, but I suspect that organic contaminants and phosphate give it much character. Don't ask me how I know. It's Irish intuition confirmed by the similar smell of wet perlite. Silt is biologically active, black clay to me, something like I would find in the filter for my aquarium or a jar of Marmite :-| "Pure" clay? That's probably like weak whiskey. I'm pretty sure that clay contains a lot of lime water and dissolved glass, but I don't think it would be clay without the carbon and carbonate. BrewJay (talk) 07:56, 21 January 2008 (UTC)

Definition or decription

Hello Ballista, I reverted your edit back to my earlier because:

1) You stated Clay is a sedimentary deposit, however some primary deposits are found

2) You stated hydrous silicate mineral, where as clay is not one mineral but a group of minerals and include, for example, halloysite, kaolinite and montmorillionite

Best regards, Andy

Would just like to point out that primary clay does not necessarily = Kaolins. Kaolins are clay minerals that are formed by the breakdown of feldspar. Formation of kaolin/ china clay is often associated with the degredation of feldspar found in basic igneous rocks such as gabbro and granite. Whilst deposits of Kaolin would probably be primary, it is possible to get primary clays that are not kaolin. A primary clay merely refers to a clay deposit that is found where it was formed. For example clay formed from mudstones could be considered primary, providing it hadn't undergone any form of transportation. — Preceding unsigned comment added by Bbbill123 (talk • contribs) 20:45, 13 June 2012 (UTC)

standards

More reference to standards, and keeping clear the difference to the standards; USDA vs BS5930 80.229.47.244 15:57, 25 June 2007 (UTC)jago25_98

Removing useful text

Hi. I just found bit of guidance from Wikipeida itself: "Deleting useful content. A piece of content may be written poorly, yet still have a purpose. Consider what a sentence or paragraph tries to say. Clarify it instead of throwing it away." This is pretty much what I have been saying all along. —Preceding unsigned comment added by 81.153.65.237 (talk) 21:37, 26 September 2007 (UTC)

To which content are you refering, please? ZueJay (talk) 02:37, 29 September 2007 (UTC)

Zuejay, this anon editor can't be bothered to a) sign up in Wiki, or b) source his edits which were mostly redundant. I think "what I have been saying all along" refers to his discussion at User:Basartalk which was a little bit dismissive on anon's part (especially since he spent more time arguing than it would take to pull out a book and source his edits). I don't see what the argument was about, nothing of much value was removed in the first place. I just pulled whatever minimal, non-repetitive information was there into a more concise description which I hope can be improved on without just reverting to an old edit by the anon user. I'm trying to find my books on stratigraphy and sedimentation, minerology, and a decent reference in "Petrology" (Ehlers/Blatt) to back up what I have written. Drillerguy 16:13, 29 September 2007 (UTC)

Anon users please sign up

It would really be helpful if anon users who want to add constructively to this topic would create user names on wiki. I just had an anon user remove an easily sourced edit (which I reverted and sourced with a widely distributed and authoritative geologic text) for some reason which I can't fathom. Not quite vandalism because, true my edit wasn't sourced initially and the user had the courtesy to comment at least to their rationale, but my edit was easily verified and following the link to either bauxite or aluminum would have backed up the sentence. Bottom line is, this is a very important topic in the earth sciences. It is only a matter of time before editors from the geology project, soil project and civil engineering project start adding to this article. Anyone who is now anon and wants to contribute should not feel bad when editors from these projects revert unsourced content.Drillerguy 15:10, 1 October 2007 (UTC)

Geologic Origin here?

Would the details of the geologic origin of the clay minerals be better placed in that article, rather than this more general one? Vsmith 16:09, 1 October 2007 (UTC)

That's a fair question. There is a little bit of disambiguation which has to happen first. F'rinstance, is this article synonymous with "clay deposits"? Even if it is, I think it is tough to talk about "clay deposits" without going into what exactly they are composed of at least in a general sense. My first inclination is to describe first "clay" with the mindset that the averge Josephine Blow is looking for in depth information about what they - in everyday experience - know as "clay". That would have to include what "clay" is composed of re minerals, the types of clays, and how those clays and clay minerals occur in large enough volume to form recognizable "clay deposits". Then go on to the significance of "clay". I think it is important to note that clay as a natural material is mined for many uses, both for it's physical properties (ceramics, building materials, drilling fluids, etc.) but also for it's chemical properties (aluminum ore, etc.). We haven't even touched the surface of clay in geologic or geotechnical engineering perspective (fat clays, lean clays, organic clays, swelling clays, etc.).Drillerguy 19:33, 1 October 2007 (UTC)

Clay - only "clay minerals" not particle size?

Anonomyous user 86.154.127.142, citing no sources, and adding no further description of what clay IS, claims (in his comment reverting my and Vsmith's edits) that laterites, which are combinations of gibbsite (a chemically weathered product of the widely recognized clay mineral kaolinite), along with concentrations of residual clay minerals such as kaolinite, illite and montmorillonite and other clay mineral sized crystals are not "clay". Well, that might be true, but I have sourced what I have written and this user can't be bothered to do the same. Nor can they be bothered to sign up an account with Wikipedia. I will track down more sources and add citations for what I write to this article. If anon user 86.154.127.142 continues to revert without citing sources I will start to flag those edits as vandalism. Drillerguy 20:19, 1 October 2007 (UTC)

Oh how very nice. Threats simply because I point out, correctly, that gibbsite is not a clay mineral. Welcome to the strange world of Wikipedia. —Preceding unsigned comment added by 86.154.127.142 (talk) 20:27, 1 October 2007 (UTC)

I will concede that I am 100% wrong if 86.154.127, whatever that entity may be, will add constructive comment to the page including citations. If you are right 86.154.127.142, that will be simple for you, and a big ole win in your column; you can lift your fingers from the keyboard satisfied that you rule. On the other hand, maybe it escaped notice that I didn't revert my own edits, only those "hopefully" uncontroversial edits of VSmith which followed. I invite you to discuss here, please do. Drillerguy 04:35, 2 October 2007 (UTC)

It is a pleasant change that you "invite" to discussions as to date you have been less than welcoming, although comments such as refering to me as an "entity" and suggesting "can lift your fingers from the keyboard satisfied that you rule" does rather counter this suggestion. I have no interest in a "big ole win" and certainly not in a discussion with someone with your apparent appalling attitude to others. —Preceding unsigned comment added by 86.154.127.142 (talk) 05:30, 2 October 2007 (UTC)

This is an article about "clay". "Clay" it is not a synonym for "clay minerals". Likewise, the description of clay minerals on wikipedia is not sufficiently inclusive, why don't you add your insight there (with references and citations of course)? Is it overly simplistic to call "clay" whatever it is that you yourself have not bothered to characterize? Please cite a reference of what a clay mineral is or is not. Please cite a reference of what a clay deposit is and what it is not. Your opinion, like mine, is worthless without a reference to back it up, all else is indeed dross. In the past, I invited you several times to cite references, not once have you done so. This isn't a personal contest even if you think it is on your end. Bring a reference to the table and make the article better by it's inclusion. If you can't cite references than your content isn't worth much. If I "warned" you, it was merely to say that the attitude of willy-nilly editing this article without references will not last long. That goes for my edits too. Drillerguy 06:51, 2 October 2007 (UTC)

Clay is a confusing term because it has multiple meanings, clay in terms of grain size is picked up on in the original article, even in this clay is confusing, different scientists have different definitions on what size a clay particle is depending on the standards used by their area of science. Clay may also be used to describe a sediment for example London Clay or Bothkennar Clay. These materials these are normally defined as having more than 50% clay minerals when wet. Finally clay minerals such as kaolinite, illite and montmorillonite can informally be called clays. Clay minerals are often smaller than 1 micron but they can be larger in this case a material called a clay on the basis of mineralogy is not a clay on the grain size. This can work the other way glacial rock flour formed as rocks are crushed by the action of ice can contain material which is clay in terms of grain size but not clay in terms of the mineral present. This confusion is leading to scientists using clay to describe minerals and mud/mudstone to discribe sediments. The problem of clay being used to discribe minerals and clay being used to discribe grain size has yet to be resolved

References:

Potter, P. E., Maynard, J. B., and Depetris P. J., 2005, Mud and Mudstones, Introduction And Overview. Springer. p297.

Reeves, G.M., Sims, I., and Cripps, J.C., 2006, Clay Materials Used In Construction, The Geological Society London, Engineering Group Special Publication, 21, p. 525.

Gibbsite is formed from the alteration of a number of aluminum rich minerals (normally feldspar or nepheline) by intense chemical weathering. It may turn into kaolin by silicification. It is not a clay mineral, it is a hydroxide however it is often considered a clay in terms of crystal size.

(Gribble, C. D., and Hall, A. J., 2001, Optical Mineralogy Principles and Practice, UCL Press, p. 303.)

From a pottery point of veiw, clay is made of sediments (of particle size <0.002mm) together with clay minerals, which are themselves aluminas or silicates, chemically bonded with water. these clay minerals have a crystalline structure. It is the clay minerals, rather than the sediment component, that give wet clay its plasticty, and cause it to shrink as it dries.

Rye, O.S 1981. Pottery technology: Principles and Function, Washington:Taraxacum p.16 — Preceding unsigned comment added by Bbbill123 (talk • contribs) 20:00, 13 June 2012 (UTC)

Clay Societies

This section is the stubbiest part of the article. Once cleaned up, the section should be moved to clay minerals. -- Paleorthid (talk) 18:27, 24 November 2007 (UTC)

report on clay

↔♣m³m²#clay is made out of fine-grained minerals and is dug out of earth in large clumps. Lcay is formed over long periods of weathering of rocks. —Preceding unsigned comment added by 72.87.235.174 (talk) 00:03, 16 September 2008 (UTC)

Ceramic material

I have removed the category 'ceramic material' for the simply reason clay is not. It can however be a ceramic raw material. This is a very, very important difference. Ceramic materials are just that: ceramic. These are man-made materials which during their formation have been subject to high temperatures to impart permanent chemical and physical changes. Whereas 'ceramic raw materials' are those materials used at the start of this process: they are the pre-cursor materials. —Preceding unsigned comment added by 210.54.238.178 (talk) 02:59, 6 April 2009 (UTC)

Re-added category. Clay is a material used in ceramics. Raw or otherwise, so the category applies. Vsmith (talk) 03:04, 6 April 2009 (UTC)

But it is incorrect! Lumping ceramic materials (which are made-made) and ceramic raw materials (very nearly always naturally occuring rocks & minerals) together is not only wrong but highly confusing. No college course, book or article on the subject ever does this. Why not simply have another category? In addition to 'Ceramic material' for such as stoneware, cordierite etc have and 'Ceramic raw materials' for such as clay, feldspar etc. Not only would this be correct but would help ensure no confusion with readers: and if Wikipedia is not here to inform correctly then what is it? —Preceding unsigned comment added by 210.54.238.178 (talk) 04:08, 6 April 2009 (UTC)

"Clay, being relatively impermeable to water"

The above is somewhat misleading. When dry and placed in water, clay will change from being a solid mass into a slurry. —Preceding unsigned comment added by 59.154.42.131 (talk) 04:10, 1 April 2010 (UTC)

Assessment comment

The comment(s) below were originally left at Talk:Clay/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

* needs wikify, restructuring and cleanup. -- Paleorthid 05:28, 2 December 2006 (UTC) With >1500 articles linking to it, high importance to Wikipedia. -- Paleorthid (talk) 17:35, 24 November 2007 (UTC) Cleanup needed in the Society section. -- Paleorthid (talk) 18:01, 24 November 2007 (UTC) Ready for peer-review towards qualifying as a good article. -- Paleorthid (talk) 18:01, 24 November 2007 (UTC)

Last edited at 06:50, 8 December 2007 (UTC). Substituted at 11:52, 29 April 2016 (UTC)

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Being Picky: What does Boggs say, exactly, about shale?

The article states, "Clay is a very common substance. Shale, formed largely from clay, is the most common sedimentary rock" referencing Principles of Sedimentology and Stratigraphy, Boggs, 2006, 4th Edition, p. 140. If anyone has access to that edition, I'd appreciate a confirmation that the reference statres shale is the most common. I borrowed from Boulder's CU library Boggs 2012 5th edition (the closest they had to the 4th) and found these quotes which come close but none of which quite say that shale is the most common...

"Mudstones and shales are abundant in sedimentary successions, making up roughly 50 percent of all the sedimentary rocks in the geologic record." p. 118

"Origin and Occurrence of Mudstones and Shales: ... The fine-grained siliciclastic products of weathering greatly exeed coarser particles; thus, fine sediment is abundant in many sedimentary systems. Because fine sediment is so abundant... mudstondes and shales are by far the most abundant type of sedimentary rock. They make up roughly 50 percent of the total sedimentary rock record. ... Nearly pure shale units hundreds of meters thick also occur." p. 122

BTW, at Glacier National Park, the shale deposits there are much thicker. After taking a Geological Society of America's 2016 Glacier Nat'l Park field trip with a dozen geologists, referring now to an online post I wrote at the time, one deposit in the park is of 30,000 foot thick thin-layered rippled slate. That's a lot more than hundreds of meters. And our guide, a local expert and professional geologist, would only quantify the massive mud deposits there as "off the scale".

Anyway, Boggs p. 122 continues, "A few shales (and mudstones)... are particularly well known owing to their thickness [though Boggs gives no range], widespread areal extent... include... the Devonian-Mississippian Chattanooga Shale and equivalent formations that cover much of North America and whose widespread extent is still poorly explained..."

So again, if anyone can confirm that Shale is the most common, per Boggs or other source, thanks! Bob Enyart, Denver KGOV radio host (talk) 21:15, 5 August 2021 (UTC)

Part of the problem is a lack of consensus, until recently, on what "shale" actually means. In his 4th edition, Boggs expresses the view that "shale" is a perfectly good term for any kind of mudrock, and if that's the definition, it's doubtless the most common sedimentary rock. It sounds like by the 5th edition, he was coming around to regarding shale as being a particular subtype of mudrock. If you can look at your borrowed copy, it would be very helpful to know what definition of shale he uses now and what distinction he now draws between shale and mudrock.

Prothero and Schwab regard shale as any laminated mudrock. Folk (much earlier) made it laminated claystone, which is slightly more restrictive -- but I suspect most laminated mudrock is claystone so it may be a minor point.

We note in the article that "shale" is still widely used as essentially a synonym for mudrock, which I think is still supportable. It is mudrock, not shale in the narrower sense, that we have good sourcing as the most common sedimentary rock. What would be ideal would be if we could find good sourcing on how much mudrock is shale in the narrow sense. We could then say something like "mudrock is the most common sedimentary rock, making up X% of all sedimentary rock " (per just about any good reference, and some give the necessary percentage) and "shale makes up X% of all mudrock". But I haven't been able to find good sourcing for the percentage of mudrock that is shale -- I couldn't even tell you if it is 10%, half, or 90%. --Kent G. Budge (talk) 22:19, 5 August 2021 (UTC)

On reflection -- since this is the "Clay" article and not the "Shale" article, the real question is whether clay-rich mudrock (claystone and mudstone, whether laminated or not) is the most common sedimentary rock. I think yes, but I agree the sourcing is not entirely solid. There is sourcing for the statement that siltstone is an unsual (therefore uncommon?) mudrock, which implies clay-rich mudrock (which would be everything but siltstone) makes up most mudrock, but that comes close to an impermissible synthesis. --Kent G. Budge (talk) 22:24, 5 August 2021 (UTC)

On yet further reflection -- "Mudstones and shales are abundant in sedimentary successions, making up roughly 50 percent of all the sedimentary rocks in the geologic record." p. 118 Both mudstones and shales are clay-rich. So I think tweaking the lead to more closely reflect this from Boggs may be the right solution. The point, after all, is to emphasize how common clay is. However, that's from 5th edition, so we'd have to update all the Boggs references to the newer edition to avoid a Boggs versus Boggs problem in sourcing. --Kent G. Budge (talk) 22:28, 5 August 2021 (UTC)

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Why people eat clay ?

people eat clay because of cravings and when they smell wet soil after raining the crave for clay . 41.114.144.52 (talk) 18:45, 15 October 2023 (UTC)