Talk:Feldspar

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This article was the subject of a Wiki Education Foundation-supported course assignment, between 9 September 2020 and 9 December 2020. Further details are available on the course page. Student editor(s): Klm10.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 21:15, 16 January 2022 (UTC)

First line first line of article

To the absolute beginner the first line of this article is confusing. The title of the article Is "Feldspar" then Feldspars plural are defined. Beginners think Feldspar is either a rock or at best a single mineral. Feldspar is the name given to a group of minerals made up of the Feldspars.Ruskin (talk) 04:51, 14 April 2017 (UTC)

Pegmatite dikes

What does pegmatite dikes mean?

I believe in the context of geology a "dike" is a place where rock type has intruded into another rock type, often as magma seeping into cracks in older rock and hardening. So a pegmatite dike would be an intrusion of pegmatite into some other type of rock. --Delirium 19:41 15 Jul 2003 (UTC)

Ok, thanks. I just found the definition on dictionary.com which I hadn't noticed before. dave 17:02 16 Jul 2003 (UTC)

Can someone help me out with the geological definition of dike at dike? Extend it to a dike (geology) page if you like... Thanks. dave 17:18 16 Jul 2003 (UTC)

Done - or at least started. Dike (geology) --Vsmith 03:16, 11 Sep 2004 (UTC)

Etymology of "feldspar"

Funnily enough, on the German Wikipedia page for Feldspar the first part of the word Feldspat "feld" is explained to have its origin in the Swedish language with "fjäll" meaning hill, mountain. I'm also not so sure about your explaination for "spat" as well. I think I heard that its origin might be German ("spalten") with the meaning cleavable. Alex, Austria

I'm not sure about the Swedish terms either, Alex. The Swedish "fjäll" means (fish)scales or shingles, not mountain. The word "spat" does not seem to exist in Swedish language (online translation only, I'm not native). Its closeness to "spalten", the German word for "to cleave" is apparent (but maybe wrong...). But I seem to remember such etymology from college. "to cleave" in Swedish is "klyva". The etymological explanation as it is now (Mar 2008):

"Feldspar is derived from the German Feld, field, and Spat, a rock that does not contain ore."

thus feldspar = "rock without ore from the field", is probably wrong. feldspar = "cleaves like fishscales" would make more sense to me. But I'm not knowledgeable enough to change anything. --83.77.134.53 (talk) 00:39, 5 March 2008 (UTC)

I´m Swedish. You got hit by two meanings of "fjäll": One is scales (mostly on fishes), the other is for the northern part of the mountainchain between Sweden and Norway. (The word also exists in Norwegian language and then covers all the way south for the higher mountins.) It is not used for other mountains in Sweden or for mountains outside Scandinavian area.Seniorsag (talk) 13:38, 20 July 2012 (UTC)

I'm no linguist, but as a geologist, I can confidently say that although cleavage is a basic, identifiable characteristic of minerals, feldspar in no way "cleaves like fishscales". Feldspar is the second (maybe the first?) most common mineral in the crust, so describing it as a field or mountain rock that does not contain ore (which is typically true) is a pretty reasonable etymology 129.138.12.142 (talk) 22:36, 3 February 2011 (UTC)

Indeed, the already cited linguists concur. [1] Cesiumfrog (talk) 14:12, 20 July 2012 (UTC)

Seriously, "spar" comes from german "spat" which means cleavage. A lot of minerals have "spat" in their german names (mainly synonymes) like baryte ("Schwerspat" = heavy spar), fluorite ("Flussspat"), calcite ("Kalkspat"). They are all synonyms for minerals with good cleavage. Baryte for example is an important Ba-ore. I never heard about the ore-interpretation. I'm a german mineralogist.

You could try it to read on the german Wiki. I don't know if it's true (no one can say that). But there are 2 possibilities. But I can't imagine, that the word "Spat" means without ore. There is no connection between Spat and ore. — Preceding unsigned comment added by 2a02:1205:34eb:55a0:182f:2414:4332:82b5 (talk) 01:41, 13 January 2018 (UTC)

I am going to fix this. An etymology is how a word originated, not what it currently means. Spat means flake or mineral that cleaves into flakes, says the German Wikipedia with attribution. Rp (talk) 07:38, 13 October 2019 (UTC)

So I did. Rp (talk) 08:27, 14 October 2019 (UTC)

Images

Please can someone give an idea of size, such as a scale bar. This is very basic stuff. Not including these is bad practice and makes the images of very little value.

Output map

This looks wrong. Each circle is said to represent a % of the top producer. The top producer is given as one country (Italy) but a number of circles of given for single countries (for example 9 in China) Surely the map should be based on countries aolone, or individual companies alone. The present design is a mess.

Images

Please can someone give an idea of size, such as a scale bar. This is very basic stuff. Not including these is bad practice and makes the images of very little value. —Preceding unsigned comment added by 81.153.64.39 (talk • contribs)

I have answered here. Best regards Rhanyeia 12:28, 16 August 2007 (UTC)

Text on map

Could some explain what "This map is consistent with incomplete set of data too as long as the top producer is known" actually means? As it is presently written it is jibberish. For example if it is acknowledged there is an incomplete set of data then it would be better not have anything - remember no data is preferable to bad data. —The preceding unsigned comment was added by 81.153.30.48 (talk) 05:57, August 23, 2007 (UTC)

I agree. It does not make a great deal of sense to me. Also data should not be published if it is incomplete. —Preceding unsigned comment added by 81.157.127.176 (talk) 21:51, 23 September 2007 (UTC)

FELDSPAR

My name is Jessica M. and i'm doing a recearch on a few different rocks but I need the type of info. that tells you where\how it was formed..please help70.225.129.44 (talk) 13:19, 29 September 2008 (UTC)

Feldspar is a mineral, not a rock. It forms in a number of conditions, but mostly under silica rich igneous conditions. 130.39.191.251 (talk) 23:06, 13 May 2009 (UTC)

More correctly Feldspar is the name of a group of minerals the Feldspars. This confuses beginners Ruskin (talk) 04:51, 14 April 2017 (UTC)

abundance

Currently the quartz page says that quartz is the second most abundant mineral (in the earth's crust) after feldspar. The silica page (quartz is a type of silica) says that silica is the most abundant mineral.

These claims are not necessarily contradictory. But it is terribly unscientific! One should avoid ever giving a bare ranking like this, because it depends on the implicit yet arbitrary choice of categorisation scheme. For example, if the earth were 36% feldspar, 34% quartz, 10% opal and 20% sand then clearly feldspar ranks first (36%>34%) but still silica also ranks first (64%). Also, by being more discriminating (say, considering separate types of feldspar, and specific types of quartz) we can make sand be the third most abundant or the first most abundant.. you see these rankings mean nothing at all, which is why the only scientific thing to do is to state the percentage (not the comparative rank) and be done with it.

In this case it would be compounded even worse: it also depends on whether the ranking is by weight or by volume or by number or atoms!

Worse, in this case, one of the pages is actually wrong (and not just implying an inconsistent categorisation). The crust (geology) page has a table saying that silica makes up 60% of the crust. But this article says that feldspar makes up 60% of the earth's crust. These are mathematically contradictory unless one counts the silicon and oxygen in the feldspar as if they were not chemically bound to anything else (but doing so would negate the whole point of comparing mineral abundances rather than elemental abundances).

Recommend a separate page for mineral abundances, and duke citations there. Cesiumfrog (talk) 04:02, 16 December 2010 (UTC)

First feldspar is a mineral group, not a single mineral. Quartz is a specific mineral and by far the most common of the "silica" SiO₂ group. Silica and sand are not minerals. As for the silica content of the crust, feldspar and most rock forming minerals are silicate minerals and contain "silica" as SiO₄⁴⁻, (Si₂O₇)⁶⁻, (Si_xO_3x)^2x-, SiO₃, Si₄O₁₁, Si₂O₅ and then the 1:2 ratio SiO₂ in tectosislicates which make up nearly 75% of the crust. Watch them "oranges and apples":). I agree though that these grand comparisons are a bit lacking and seem contradictory - especially for those who don't know the details. And looking at the silicon dioxide page, the statement: Silica is the most abundant mineral in the Earth's crust. needs editing as silica is not itself a mineral and the main mineral form of silica, quartz, does not make up 60%. Vsmith (talk) 15:53, 16 December 2010 (UTC)

And the table in the crust (geology) page is presenting the chemical make-up with the SiO2 as the chemical oxide of silicon and not the mineral quartz. Vsmith (talk) 16:06, 16 December 2010 (UTC)

Rotten link

Reference 2 is a rotten link to http://www.ima-na.org/about_industrial_minerals/feldspar.asp and it's cited in five places in the article. I don't know how to remove all the references so am flagging it here for some caretaker's consideration. — Preceding unsigned comment added by 85.237.197.79 (talk) 02:14, 28 July 2013 (UTC)

I've updated the link - thanks for spotting it. Mikenorton (talk) 11:12, 28 July 2013 (UTC)

Color

The side bar lists several colors, but there's no mention in the article (that I can find) of what causes the different colors--impurities, different amounts of Na/K/Ca? (The article on granite suggests that it's the K feldspars that have a pink color.) And that to me is one of the most interesting properties--easily observed in different kinds of granite. Maybe someone could add an explanation of the color? Mcswell (talk) 01:58, 29 April 2015 (UTC)

Color in minerals is really complicated and not as well understood as you'd think. K-spars are often pink, but can also be white, tan, red, yellow, or even green, blue, lilac, or other colors. "Color in feldspars" by Hofmeister and Rossman, Chapter 11 in this book here http://www.minsocam.org/MSA/RIM/rim02.html is probably what you're looking for. 128.97.31.102 (talk) 20:03, 28 September 2015 (UTC)

Orthoclase vs. potassium-feldspar?

Is there any reason why pure K-feldspar should not be referred to as "orthoclase" in the Compositions section? This is always what I've heard it referred to, and it seems that calling it potassium-feldspar might be confusing with other intermediate K-Na compositions, which are more often called "K-feldspars" or "alkali feldspars." Thoughts? Schlockading (talk) 21:05, 24 June 2015 (UTC)

Sanidine is another (higher temperature) K-feldspar, so that would be the reason I think. Mikenorton (talk) 22:41, 24 June 2015 (UTC)

I've seen orthoclase used as a general term for all K-rich feldspars (mostly by mapping geologists), but more properly it refers only to those K-spars with an intermediate range of aluminum-silicon disorder. Sanidine is highly disordered; microcline is mostly ordered. Also, alkali feldspars with intermediate composition should be referred to as just that. 128.97.31.102 (talk) 20:12, 28 September 2015 (UTC)

External links modified

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External links modified

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Possible removal from list

An entry in List of colors: A–F contained a link to this page.

The entry is :

• Feldspar

I don't see any evidence that this color is discussed in this article and plan to delete it from the list per this discussion: Talk:List_of_colors#New_approach_to_review_of_entries

If someone decides that this color should have a section in this article and it is added, I would appreciate a ping.--S Philbrick(Talk) 14:41, 20 August 2018 (UTC)

Weathering Section

I'm adding to the section on weathering with information about chemical weathering. Klm10 (talk) 03:08, 9 December 2020 (UTC)