Talk:Lycurgus Cup

Picture

May be a bit late but I suggest this article might be complimented by an animated gif that shows light in front, light behind, light in front etc Victuallers (talk) 14:57, 19 September 2010 (UTC)

With a drawing? By all means, but I haven't a clue how to go about that. A better green photo would help; I may do that one day. Johnbod (talk) 17:40, 19 September 2010 (UTC)

The Gold is not ground

The text first says, incorrectly, the gold is ground, and then says correctly the gold is precipitated as a colloid. It is not ground first, but dissolved in the glass, and then precipitated. See also Colloidal gold to understand the process. Colin McLarty (talk) 23:58, 31 August 2013 (UTC)

I'm don't think that's what the sources say. Your "dispersed" was next to meaningless to non-specialists without explanation or a link (how could it not be dispersed in the normal sense of the word?). Have you any sources for how the Romans did it? I can't access Henderson now, and this source mentions "ground gold". What does "dissolved in the glass" mean, in terms of process? I find it hard to imagine that whatever the actual process used, it did not involve grinding the gold as finely as possible at some stage, as the refs suggest. Johnbod (talk) 03:31, 1 September 2013 (UTC)

See the explanation on p.3 of http://people.uic.edu/~viveks/Publications_files/Sharma_GoldReview_2009.pdf involving Faraday. That is exactly what the present text means when it says "These particles were precipitated as colloids." That is the only way it has ever been done. It is impossible to grind anything to this size that is so extremely malleable as gold or has such good tensile strength. Colin McLarty (talk) 21:51, 1 September 2013 (UTC)

Where's your ref for that? The specialist sources on the cup steer clear of mentioning salts, and note that they think the gold may have been present only as part of silver. They notably avoid specifying the exact method, and seem unclear how the Romans managed to do it. I have found the new home of the main paper available online, Freestone et al., & added more from that. I also note that references to "Barber", the first paper to cover the nano-aspect of the cup have been added by someone else (with an intriguing user-name I might add), who did not adjust the text previously there. Johnbod (talk) 03:51, 2 September 2013 (UTC)

And here's the Smithsonian talking about "ground-down"; the one thing you don't find is talk of the cup and salts of gold. Freestone also talks of "The fine particles of sodium chloride observed (fig. 5) are likely to have exsolved from the glass during the heat-treatment that caused the crystallisation of the alloy particles, ..." Johnbod (talk) 04:12, 2 September 2013 (UTC)

Your quote of Freestone says it: The sodium chloride was not ground down, it was exsolved from the glass in the same way as the gold alloy crystallized from the glass. A fun Smithsonian blurb on Roman nanotechnology is not serious history. Colin McLarty (talk) 15:31, 2 September 2013 (UTC)

Well not really. One hardly needs to grind down salt. It doesn't cover in what form the "alloy particles" entered the glass mix. Unless you have specific references, I'm not really interested in more "they must have..." arguments, given my points above. Johnbod (talk) 15:54, 2 September 2013 (UTC)

Okay. Anyone who wants to know how it was done can see the Freestone quote you gave, or Colloidal gold for more detail, or the reference http://people.uic.edu/~viveks/Publications_files/Sharma_GoldReview_2009.pdf I gave above for much detail. Colin McLarty (talk) 16:26, 2 September 2013 (UTC)

Unfortunately neither of those are clear about either the process or even the chemistry used for the Roman glass. I just don't think it is known with certainty, as Freestone implies. Johnbod (talk) 16:32, 2 September 2013 (UTC)

So you agree we do not know they ground the gold? We only know it was somehow dispersed? Colin McLarty (talk) 15:13, 4 September 2013 (UTC)

You haven't actually said (nor have your sources) how the gold got into a "dispersable" state, but presumably you are thinking of gold salts. But the references concerning the cup are noticably lacking in references to gold salts (as opposed to salt) and some refer to "ground" gold. Johnbod (talk) 16:51, 4 September 2013 (UTC)

I am not thinking primarily of gold salts. The article currently gives two ways it might have been dispersed accidentally: it could have been present in silver unknown to the glass makers or it could have been minute bits of gold leaf around the glass shop. That implies it could have been deliberately added as gold leaf to melt into the molten glass. It might also have been a minute presence in the sand used or other additives. The light hearted press release saying it was "ground" by "Roman nanotechnicians" is not a serious source. Colin McLarty (talk) 17:50, 4 September 2013 (UTC)

I also linked to Collins above. Johnbod (talk) 20:54, 4 September 2013 (UTC)

Roman Nanotechnology

There is a dispute about ancient Rome's understanding of the process of making dichroic glass. This is not an academic dispute! The issue is whether it is appropriate to include information about ancient Rome's understanding, whether it be a fundamental knowledge of nanotechnology (this is rhetorical, of course), or merely a simple cause and effect understanding of what they were doing (i.e. ancient China could not have known the molecular science behind gun powder, but they definitely knew how to make it by more than mere accident) in an encyclopedia article. I think that this information is speculative, or otherwise unnecessary. That is to say, it is not necessary to point out that ancient Rome did not grasp nanotechnology, and that discussion of whether the creation of dichroic glass was an accident or a known process (that is, the person making the glass knew that it was going to have a "color-changing" effect, and was not merely adding finely ground gold and silver to make it prettier or more valuable) is speculative. My apologies if anyone misunderstood my point and was offended. 74.197.184.250 (talk) 04:08, 31 December 2013 (UTC)

See the article: "To a conventionally composed Roman glass flux 330 parts per million of silver and 40 of gold were added: "These particles were precipitated as colloids ..." and the section above - "grinding" would not be enough to get 40 parts per million as colloids. Even if the Romans had simple magnifying lenses, as some scholars have suggested, the particles would need to be too small to see even with those. The language used in the article reflects the source and is hedged about with caveats and qualifications, which I have bolded for your convenience:

The exact process used remains unclear, and it is likely that it was not well-understood or controlled by the makers, and was probably discovered by accidental "contamination" with minutely ground gold and silver dust. The glass-makers may not even have known that gold was involved, as the quantities involved are so tiny; they may have come from a small proportion of gold in any silver added (most Roman silver contains small proportions of gold), or from traces of gold or gold leaf left by accident in the workshop from other work. The very few other surviving fragments of Roman dichroic glass vary considerably in their two colours.

I might add that the quantities surviving, even as small fragments, are much more consistent with an occasional lump of glass turning out this way, and then being re-melted for luxury use, than with an effect that glassmakers knew how to reproduce. Johnbod (talk) 12:37, 31 December 2013 (UTC)

Lycurgus cup is not made with "dichroic glass"

Dichroic glass is a type of glass made with alternating metal or metal oxide thin FILMS, layered and embedded in the glass. It can be done via deposition, sputtering etc and the layering yields a color change when illuminated at different angles due to interference . Lycurgus cup contains colloidal gold and eventually colloidal silver which have nothing to do with alternating thin films of gold and or silver. True dichroic glass changes color according to the angle of incident light, whereas the glass from the Lycurgus cup -a glass akin to "cranberry glass" (see wikipedia article) - changes color when lit from the inside VS lit from the outside, regardless of the angle of the incident light rays. This color change has yet to be named and if some museums or artbooks classify the lycurgus cup as being "dichroic", well it is simply not accurate at all. The Lycrugus cup is a special type of cranberry glass but does not contain any layering of precious metals in film form, as there isn't one single study or analysis that will confirm the presence of metal layers: the gold and silver is only present in colloidal form dispersed evenly in the glass matrix. (isp, not signed)

• "Accurate" according to who exactly? Unfortunately there are a raft of sources, including scientific ones, that don't agree with you there about the terminology - do you have any at all that do? Who exactly "revised" the definition of "dichroic" and when? Any sources? I can't imagine why you would think that the invention of a different new type, with rather different properties, would somehow displace the old meaning, making it "outdated". This is a very strange idea. "dichroic" simply means "two-coloured" and both types are that. The cup is absolutely not made of Cranberry glass, which has only one colour whatever you do to it. Johnbod (talk) 19:40, 1 January 2014 (UTC)
  • you really have no clue of what dichroic means and have certainly not read any precise definiton, not even the one present on wikipedia. "Two coloured" is only related to the ancient greek etymology, but dichroism is in fact two clours that SIMULTANEOUSLY appear but INDEPENDENTLY at different VIEWING angles , just read the wikipedia article. such an effect in inherent to a specific CRYSTALLOGRAPHIC structure which permits light to be transmitted at a certain angle in a certain wavelength and at another angle at a different wavelength, but glass is amorphous - no crystals are present- and the Lycurgus cup is coined "dichroic" by some authors only because a CONSENSUS has not uyet been reached for the exact term. Freestone calls the material "dichroic" with quoting marks in a 1990 paper , and in 2007 calls it dichroic in a study but concludes by coining it "Lycurgus effect" since the phenomenon is unlike dichroism encoutered in crystals and very different : the Lycurgus glass does NOT depend on viewing angle but only on two specific light source positions -inside the cup or outside the cup- , for example when viewing the cup illuminated with a source outside the cup, at all viewing angles the cup will appear greenish, unlike what would happen with a genuinely dichroic material when the material is oriented at different angles towards the observer, two different colors appear . Modern "dichroic glass" as coined by the companies who produce this sort of material, is a composite made of stacked layers of glass and ultrathin metal film layers, which happen to transmit light when viewed at different angles, which is an effect similar to genuine dichroism encountered in crystals due to inteference phenomenon when the light hits the metallic films embedded in the glass composite. none of the modern dichroic glass available are made with colloids of gold or silver, they're all based on layering of oxides or metals within a glass matrix. By the way, Freestone acknowledges in the 2007 paper the fact that the Lycurgus glass can be classified as a type of "ruby glass" although it contains more silver than gold, probably colloidal electrum as he proposes.

If you're familiar with optical effects present in glass, gemstones etc, you'll notice that names fluctuated with time until a consensus was reached but in the meanwhile imprecise names were used . Dichroism being a type of pleochroism, check out the definitions in wikipedia. The Lycurgus effect is partially due to scattering of light by the silver gold alloy colloids in the glass matrix, which is entirely different from any crystallographic property, yielding a completely different result: all that is common between lycurgus glass and dichroic crystals (and dicrhoic layered composites) is that they display two different colors. You CANNOT decide that anything displaying two different colours is "dichroism": a good general counterexample is that many materials when illuminated with blacklight (a specific wavelength of UV) exhibit a different color than when illuminated by conventinal means (daylight, lightbulbs etc), yet are NOT dichroic by any means! Another counter example showing that you (and some unscrupulous authors) are wrong about tossing random names for an effect simply because the etymology is reminiscent of a similar result.. is that the gemstone alexandrite displays one color when illuminated by sunlight , but another when illuminated by electric standard lightbulbs, yet alexandrite is NOT dichroic but has been mistaken as such in the past. Now the mistake has been corrected unanimously without questioning and alexandrite is associated with an effect that is specific to some types of chrysoberyl being illuminated with different TYPES of light sources but NOT under different VIEWING angles under one and only light source (as in dichroism). This is what defines the "alexandrite effect" in literature. Educate yourself and do not coin all effects displaying "two colours" dichroism. Such mistakes are unfortunately very common in outdated literature and sometimes in recent papers that relate to a rare effect that has not yet reached a consensus as to its precise nature and ends up with a wrong name -for the while being- . (isp unsigned)

It's not me deciding anything - I'm just following the sources. I suggest you do the same. Our understanding of the way the effects happen is the same, as should have been obvious from the start, but you think, on the basis of no evidence whatsover, that the long-established and general term for the Lycurgus effect has become "outdated". It hasn't, and no sources say it has. You have left a mess over at the other article btw. I'll look at that tomorrow. And learn to sign your edits please. Johnbod (talk) 05:54, 2 January 2014 (UTC)

the sources say "dichroic". But Freestone says in 1990 dichroic and in 2007 updates with "Lycurgus effect" . I left a "mess"? The mess is you deciding that Lycrugus glass is dichroic because some authors are imprecise and do not follow the PRECISE definitions of pleochroism .

I gave you an example of stones that have been coined "dichroic" in the past but now are not any more because it wasn't dichroism, I also demonstrated that displaying "two colours" is absolutelyu not a synonym of dicrhoism and that dichroism is only one type of optical phenomenon implying tow colours but only at different viewing angles. The "dichroic glass" article is rather on the right path. by the way, there are MANY sources that cite Lycurgus glass as being a specific type of ruby glass or more precisely a silver-gold alloy doped glass similar to ruby glass . Just read the paper I cited in the article which precisely cites ruby glass production thorugh various historical periods and their methods. — Preceding unsigned comment added by 82.240.163.245 (talk) 06:16, 2 January 2014 (UTC)

"Precise definitions" by who? Where? Similar to cranberry glass is not cranberry glass. You are indulging in original research and synthesis of sources, which is not allowed on Wikipedia. You should be devoting your efforts to persuading the British Museum and other sources to change the terminology which they continue to use. If enough of them do, we will change terms here. If you can find ANY reliable source that specifically challenges the description of the cup as dichroic, that would be worth mentioning in a note or the text. Freestone et al in 2007 say in their 3rd para "the glass of the cup is dichroic" and in their final sentence talk of "red-green dichroism"; it is pointless to try to use him as a reference against precisely that statement! You try to use Freestone et al against the BM's "outdated" and "unscrupulous" use of the term, but of the four authors, Freestone is ex-BM and the other 3 were all then and are now BM scientific staff; almost certainly one of them wrote or checked the very BM page you complain about. Here's a "precise definition" of dichroic glass from the 2005 book Looking at Glass: A Guide to Terms, Styles, and Techniques, By Catherine Hess. But just wrong according to you - see below also, and Nanoethics: Big Ethical Issues with Small Technology, 2009, p.15, and An Introduction to Archaeological Chemistry, 2010, T. Douglas Price, James H. Burton, and The Science and Archaeology of Materials: An Investigation of Inorganic Materials, 2013, Conservation and Restoration of Glass, 2008, Sandra Davison, R.G. Newton. And so on down this google books search on "Dichroic Lycurgus". But they're all wrong, and you're right. Johnbod (talk) 10:54, 2 January 2014 (UTC)

All these books simply adopt the ACTUAL terminology which is not only imprecise but wrong, imposed by the British Museum curators ans experts working for them decades ago to call the glass "dichroic" . The same way the gemstone alexandrite was called "dichroic" (and still is in low vulgarizing books who plagiarize unrevised material) when in fact studies have shown later it wasn't dichroic at all and reacted differently to different light sources ( daylight vs incandescent) leading to a CORRECTION, decades later, stating the effect as ALEXANDRITE EFFECT, specific only to certain types of chrysoberyl. today, any serious book about gemstones will explain the difference between the alexandrite effect and true dichroism beacuse pleochroism is oneof many RADICAL METHODS TO DISTINGUISH GEMSTONES. Reacting differently to reflected or incident light is by no means a definition of dichroism, any search in googlebooks and you'll see for yourself , suffices to check for crystallography and optics books. Educate yourself and understand that some disciplines are profoundly DISAGREEING on certain grounds. The true experts are those working in optics and crystallography, they'll have the last word since they are the ones who propose and correct the terminology associated almost exclusively with their field of studies, dot. there are plethora of books written by the British Museum who explained in detail "how to restore greek marble statues" and "their true color" , with plethora of scientists who imposed their beliefs by telling the public the statues and temples have always been marble-whitish. These "experts" who really had a supposedly high education, started to acid bleach and sand the said statues and temple stones from Greece, ruining the outer layers, claiming they analyzed them and that they consisted of dirt and other pollution residues. Truth is, we recently discovered and widely accepted they were wrong and that the outer "dirty" layers were in fact remnants of POLYCHROMIC PAINTINGS . Museum experts, their "terminology" and their "methods" ... a humble expert relies on labs and doesn't impose his weird terminology, alas to honor certain discoveries and archaeologists, incorrect terms are hastily chosen ansd remain for too long. Do you need more examples? The layers in Mycenae are still called "Troy I, II, II etc" although there is no proof it was Troy, yet even if it had been some layers correspond to periods that would have predated the fabled trojan wars, but in "honor" of Schliemann, the layers are still called "Troy". Comprende amigo? how will we call the true trojan layers in the ground if ever we happen to discover a city that inspired the greek myths of Troy? "New Troy"? "Real Troy" ? Now those who discovered the Lycrugus cup was made in glass instead of gemstone (another goofy archaeology "expert" assumption hastily made: "it's a gemstone, because I decided it's a gemstone..." ) decided to call it "dichroic glass" and the term has been alas accepted even though it severly deviates from the true definiton, by far. — Preceding unsigned comment added by 82.240.163.245 (talk) 02:45, 3 January 2014 (UTC)

Leaving us back where we started. The article reflects the sources. You think they are all wrong, and you should try to get this accepted outside Wikipedia, which will then change to reflect them. Johnbod (talk) 04:31, 3 January 2014 (UTC)

No this leaves you and the term dichroic (when speaking of roman glass) in an artistic blur. Archaeology specialists decided to coin roman glass that exhibits color changes "dichroic" yet it does not comply with the definition of pleochroism AT ALL. No need to have this accepted outside wikipedia, it's a fact, and I'll have to accept the fact that they accept the term.... Some terms are associated with an array of concepts or things that sometimes do not have much in common, that is also a fact. You completely disregard what I said about the alexandrite effect, that it was erroneously coined "dichroism" until now but still some low quality books plagiarize old sources and repeat the error, although rarely since the term "alexandrite effect" is now the only correct term and is fully understood and explained. The wikipedia article you consider as "yours" does NOT reflect the sources, since the present wikipedia article doesn't mention at ALL the fact that the artisans were attempting to produce ruby glass but ended up with the glass blank that ended up after carving into the Lycurgus cup and that is not acceptable. Many sources including the ones YOu cited, CLEARLY mention what I just said now. — Preceding unsigned comment added by 82.240.163.245 (talk) 06:46, 3 January 2014 (UTC)

"the fact that the artisans were attempting to produce ruby glass but ended up with the glass blank that ended up after carving into the Lycurgus cup..." this is not a fact at all. Nor is it included in the list of possible ways the Romans ended up with the Lycurgus glass by Freestone et al. I don't think the Roman made gold ruby glass at all, or knew it existed. You yourself quote lower down from one of the refs I produced: "The artisans responsible for these works were not aware that they were using gold nanoparticles to produce ruby glass ..." We simply don't know how or why the Romans ended up with the block at all, and all the sources are very cautious in speculating about this. Evidence? Johnbod (talk) 16:00, 3 January 2014 (UTC)

Corning Glass Works have duplicated recently the Lycurgus glass

in the paper 2007 by Freestone & al "Lycurgus cup : a roman nanotechnology" , the authors mention and SHOW pictures on page 273 figures 6a and 6bof a blank made RECENTLY by Corning Inc. , as a reproduction of the Lycurgus cup material. it displays the exact same properties as the original glass. Wikiepdia member "Johnbod" decides that this doesn't please him and simply vandalizes this paragraph with no valid reason whatsoever. there are numerous sources mentioning Corning's experiments in duplicating the glass but Johnbod decides to eras anything mentioning that the glass has been duplicated. What remains a mystery is the exact methods used by the ancient romans, NOT how to obtain the same material with modern means. WHICH ARE TWO SEPERATE CONSIDERATIONS. — Preceding unsigned comment added by 82.240.163.245 (talk) 06:40, 2 January 2014 (UTC)

I was reverting your insertion of incorrect and badly-written (meaning of "coining" etc) material in the lead. I have no objection to the Corning experiment being mentioned if it is done accurately, which I have now done. It was already referenced. But as you point out, we still don't know how the Romans did it, which is the important point here. Johnbod (talk) 10:58, 2 January 2014 (UTC)

You DID have an objection about the Corning reproduction glass blank since you reverted all edits. I placed it back in the article and NOW you finally approve, leaving it as it is. The master approved.... you know wikipedia doesn't belong to you, it's open to anyone who follows the rules and writes articles backed by valid REFS, I'm not making up anything here, as opposed to what you're implying about me. This has to change. — Preceding unsigned comment added by 82.240.163.245 (talk) 02:57, 3 January 2014 (UTC)

Greetings:

 Oceana Stained Glass of Arizona (may now be defunct) made a near duplicate to the glass in this article circa 1985-1990. 

It's name was "Dessert Rose". I used it in several projects as a working stained glass artist during that time. It was referred to as Dichroic when I purchased it. The makers acknowledged the use of silver in the formula, which was the result of an attempt to duplicate colors made by Tiffany & Co. in the previous century.

  I think we need to look at the word itself to resolve the issue that is so thoroughly argued on this page. 

"Di"=2 "chroic"=color. Literally, "2 color". This, I know, is not a precise technical term definition sought by one of the parties in the argument, but it has been long-used as a description of commercial product (i.e. Stained Glass), and therefore should remain as a valid descriptor of this glass. The method of how the effect is achieved seems to be secondary to the the description provided by the name.

  The term dichroic is indeed misleading, even for this glass. While it does appear greenish-yellow in reflected light, 

it turns a vivid rose hue in transmitted light. This does not take into account the translucence of the glass, nor the special cases when there is both reflected light and transmitted light. During these times, other hues are produced by Fourier mixing of the different frequencies (colors) of the of light arriving from different angles.

  My artwork using this glass is unusual, because I used it with several other specimens of Dichroic Stained Glass

made with different techniques, resulting in panels that changed color constantly throughout the day. I have pictures, may post elsewhere to demonstrate the effects. davidsealketchupman_9ahotmail98.222.170.118 (talk) 14:53, 5 September 2014 (UTC)

glass from Lycurgus cup is really a type of ruby glass, with valid ref

"Glasses coloured by colloidal platinum are examples of " ruby glass ", a term applied to those coloured red by colloidal gold and copper but now extended to cover glasses containing colloidal platinum and silver, even though the colour is different." taken verbatim from the study "The platinum metals in glass" , by M.G. Hawes , The Platinum Metal Rev., 1957. http://www.platinummetalsreview.com/pdf/pmr-v1-i2-044-048.pdf The Lycurgus cup being made of a glass doped with colloidal particles of a silver and gold alloy is thus a type of ruby glass, in addition of being a so-called "dicrhoic glass" in literature as well. — Preceding unsigned comment added by 82.240.163.245 (talk) 07:38, 2 January 2014 (UTC)

Oh, so your 1957 is not outdated, but my 2013 paper is (pp. 65-66). Right, got that. Johnbod (talk) 11:30, 2 January 2014 (UTC)

Johnbod, you haven't understood anything. The 2013 paper you're showing me doesn't "prove" the glass to be supposedly "dichroic", it simply admits it as a fact without further proof as the paper is not meant to prove it or not, the subject of the paper is completely different than this topic. NOWHERE DOES IT STATE THE LYCURGUS CUP GLASS ISN'T A TYPE OF RUBY GLASS, INSTEAD THEY EVEN CLASSIFY IT AS RUBY GLASS!! You're genuinely dishonest and have not even read the paper you're tossing me. The paper I put forth (the 1957 one) is a paper specialized in INDUSTRIAL GLASS MAKING with PLATINUM AS A METAL DOPANT for various uses , effects and applications. I sincerely think this expert is much more AWARE than people dealing with medical imagery (your 2013 paper) as to what is called what in terms of GLASS TERMINOLOGY, my friend, still even the 2013 paper you showed me says the Lycurgus cup is an "EARLY EXAMPLE" of ruby glass. just read the damn paper ! The 1957 paper PRECISELY names what is what in terms of being "RUBY GLASS" and it states that gold, silver, platinum, and other precious metals (other platinum family members) as dopants , precipitated as colloids in the glass, make the glass a RUBY GLASS. You CANNOT DELETE MY VALID REF as you are trying to do. Do you want some unworthy refs? look for the ones you added on the wikipedia article "dichroic glass" : the definition you put comes from a CATALOG of glasses, a book dealing with the artistic classification of glasses, with no scientific opinion whatsoever, nor inline refs. That's worth nothing in terms of scientific credibility. Worse, their definition of "dichroic glass in that book is that of ancient (supposedly) "dichroic" glass (the one with gold, copper or silver colloids in the glass matrix) , not that of modern dichroic glass which is semi transparent, a stacked composite of glass and foil, and is truly pleochroic. Outdated, not aware of what existed in the times that the book was published and zero scientific value, this resumes your book about "glass" : a vulgarizing simplistic book for museum lovers and artists . If the expert in the 1957 paper says that in the GLASS TRADE ALL GLASSES DOPED WITH PRECIOUS METAL COLLOIDS ARE TYPES OF "RUBY GLASS" , then it is true unless YOU find another paper stating the opposite clearly, black on white. Unfortunately for you and your odd beliefs, you'll never find such a paper. If you imply I'm lying, just check MY ref in google, the entire PDF is available on the web, LEGALLY. — Preceding unsigned comment added by 82.240.163.245 (talk) 02:17, 3 January 2014 (UTC)

Fully protected for a week

Hopefully the content dispute can be sorted out by then. Dougweller (talk) 12:58, 2 January 2014 (UTC)

I am upset about this Johnbod taking over the article as if it were his "property". First of all, I have shown examples and given my opinion, but let's take a real look inside his "arguments " such as this "2013 paper" which supposedly states the Lycurgus cup is not a ruby glass but dichroic, and I say supposedly, because they admit both terminologies, dichroic AND ruby glass, suffices to take a minute and read the intro. http://books.google.co.uk/books?id=Ij5xe1V9Kw4C&pg=PA65&dq=Dichroic+Lycurgus&hl=en&sa=X&ei=S0rFUo6FEZKihgfJz4CoAQ&ved=0CDQQ6AEwAA#v=onepage&q=Dichroic%20Lycurgus&f=false

First of all it is a medical paper studying the application of colloidal gold in modern medicine. ONLY IN THE INTRODUCTION do they mention the Lycurgus cup as a generalistic description of ancient use of colloidal gold. Excerpt from the 2013 paper (chapter 3 page 1, introduction) that Johnbod shoves in my face but that he clearly didn't read : "The spectacularly dichroic Lycurgus cup is a still earlier example , probably dating back to fourth century Rome. The artisans responsible for these works were not aware that they were using gold nanoparticles to produce ruby glass but this is exactly what they were doing by adding a small amount of chemically treated gold to the glass" So here it is, in the same paper that is being presented to me as a counter argument, in fact the authors IDENTIFY the LYCURGUS CUP GLASS WITH GOLD RUBY GLASS, but also say that it is dichroic !!! What bothers me is they assume -only in a few lines - all sorts of things relating to archaelogical findings they've plagiarized form history books, just to begin the topic , which is very common, to get the reader interested and excited about colloidal gold. For example they state verbatim : "Introduction. Step into a mediaeval cathedral and admire the deep ruby reds found in the stained glass window and you could be witnessing an early application of gold nanoparticles" . Unfortunately for them, all modern studies, and I say ALL, show that stained glass windows were coloured red with copper salts and or oxides, no gold whatsoever, its a hasty conclusion made by selfrighteous "experts" long ago who neglected to analyze the said stained windows. Proof is Freestone & al in the 2007 paper "Lycurgus cup: roman nanotechnology" http://master-mc.u-strasbg.fr/IMG/pdf/lycurgus.pdf state CLEARLY that (excerpt taken as is) "However the colouration of glass by gold was discovered,it appears that replicating gold ruby was a challenge to the Roman glassmaker; the technology was very restricted and does not appear to have outlasted the fourth century. While the production of red glass using gold is mentioned in medieval Islamic writings, examples of such glass have yet to be confirmed. Although the red “stained” glass of medieval church windows is sometimes suggested to be gold ruby, the colourant has been found to be copper in all cases so far analysed." -HAS BEEN FOUND TO BE COPPER IN ALL CASES-, says an expert who really has analyzed all sorts of historical glass for museums (yet accepts the term "dichroic glass" for the same reason). here we have opinions that are DIRECTLY opposing, one is simply speaking of archaeological findings as an intro to his medical subject ( use and application of gold colloids as a treatment), the other speaks of numerous analysis he and or his fellow researchers (in the same field ) have performed. Which ref is "more" valid as to medieval windows being doped OR NOT with gold colloids is up to you. Personally, I choose the Freestone paper dedicated to Lycurgus cup the valid one.

now onto the Lycurgus cup being "ruby glass" or not... Freestone & al. in the same paper speak of the fabrication of ruby glass and many hypothesis as to how they may have produced it, including the the Lycurgus glass which has not only gold but silver colloids as well. Freestone goes on, another excerpt from page 275 where he identifies the Lycurgus glass as analogous to gold ruby glass since it was produced according to him by accident: "Freestone et al. have speculated that the oxidised by-products of metallurgical processes (“dross”,“slag” etc)were sometimes acquired to colour glass, and that this might explain how the “Lycurgus effect” was discovered [44]. It would also explain the relatively high levels of copper and lead oxides which are also present in the glass. However, there are a number of other possibilities which allow for the chance “discovery” of gold ruby,including accidents in the production of glasses with gold leaf decoration."

Now let's hear an expert in glass being doped with platinum, gold, silver, copper and many other metal colloids, for industrial applications: M.G. Hawes in a paper entitled "The Platinum Metal Rev. Vol1, Issue 2 , 1957" http://www.platinummetalsreview.com/pdf/pmr-v1-i2-044-048.pdf says on page 45 : "The Mechanism of Colour Formation.Glasses coloured by colloidal platinum are examples of " ruby glass ", a term applied to those coloured red by colloidal gold and copper but now extended to cover glasses containing colloidal platinum and silver, even though the colour is different." This means that unless someone demonstrates something opposite such as "only glass containing colloidal gold -and no other metal colloid- is called ruby glass " , then me must accept it, the same way a part of the scientific community uses the term "dichroic glass" when mentioning roman glass that transmists and reflects light in different colours. It is accepted, but wikipedia member Johnbod decides that we will ONLY accept the term dichroic glass. I think a compromise should be reached, as clearly the glass from the Lycrugus cup is a type of ruby glass and although the article is from 1957, I haven't read ONE paper that says this so called dichroic roman glass from tjhe Lycurgus cup isn't a type of ruby glass, instead they ALL explain how romans when melting various types of ruby glass or recuperating slag or even using gold or electrum foil to decorate glass may have attempted to produce standard gold ruby glass artifacts and ended up with the silver-gold colloid doped glass seen in the Lycurgus cup, which happens to behave unlike standard gold ruby, by changing colors according to how it is illuminated or as they coin it "ancient dichroic glass" even though it isn't appropriate considering the definitions seen in books relating to optics , crystallography etc. but is still accepted as such when dealing with ancient color changing glass containing colloidal metal. Let's not forget that today, "dichroic glass" is a term used for two completely different types of glass : antique roman glass ( and modern reproductions) that changes color in reflected light vs transmitted light... and a modern composite material made of stacked layers of ultrathin metal foil and glass , which behaves in a truly dichroic manner, which is when orienting the glass under a fixed light source, it gives one colour or the other depending on the viewing angle (and can only be produced industrially since the metal is deposited via sputtering, CVD, PVD etc). The fact that the Lycurgus cup article disregards completely the subject of "ruby glass" which it is, at least a unique variation , is unacceptable. (this being said, the "cranberry glass" article exists on wikipedia but it should be renamed "ruby glass" with gold ruby glass being a paragraph so that other types of ruby glasses could be added later on). The consensus in the Lycurgus cup wikipedia article should be that the glass is called dichroic glass (not to be confused with the modern composite of the same name) and is a rare (unique) type of ruby glass, with explanations following . — Preceding unsigned comment added by 82.240.163.245 (talk) 04:10, 3 January 2014 (UTC)

I have no objection to the similarity with Cranberry glass/ruby glass being noted, and that this may be considered as a wider grouping to which the ancient dichroic glass belongs. But these were not the changes you made, as you well know. It would help if you clarified that you know accept that your original conttention that (section header above) "Lycurgus cup is not made with "dichroic glass"" is just wrong. But the sources do not support calling the cup an "example" of ruby glass, especially if all reference to dichroic glass, the term they all use, is removed. A variant type maybe, but the cup is not actually ruby glass as that term is used by all, because its properties are very different. I don't think there is in fact any evidence from archaeology supporting ancient "standard gold ruby glass". The Lycurgus Cup is not unique in anything except being complete and in its quality; there are a small number of other ancient pieces with the same properties, as you'd know if you had actually bothered to read the article, or Freestone etc. I notice you have still completely failed to produce any sources at all supporting your narrow definition of "true" dichroism, not that it really matters what the definition in say crystallography is, because dichroic glass does not involve crystals, and it is very common for technical terms to have different meanings in different fields, without people throwing tantrums and demanding the World Federation Police sort the matter out. Johnbod (talk) 04:56, 3 January 2014 (UTC)

Whether you have an objection or not has no relevance, the validity of the refs count, and since the word dichroic is accepted by a certain part of the scientific community to describe a glass that changes colour due to a particular type of scattering in fact, then so be it, even if it isn't correct. Still many authors consider the Lycurgus cup not only ancient dichroic glass but also RUBY GLASS and MENTION it, as in your "2013 paper" from which I extracted the part where they clearly say that the Lycurgus cup was an "earlier example" BUT YOU STILL DENY IT NOW. I think you should simply shut up and refrain from posting things such as "you failed to give a valid definiton of dichroism" because first of all this is your work to find out what I've already studied, secondly there are ALREADY WIKIPEDIA PAGES referring to dichroism and pleochroism in general, of which you ignore EVERYTHING because you didn't take the time to read them, but here is one excerpt for you taken from a vulgarizing book published by Wiley , page 249 : "If uniaxial or biaxial crystals are viewed by transmitted linearly polarised white light, many will be seen to change colour on rotation. Uniaxial crystals may display two colours (dichroism) and biaxial crystals three colours (trichroism). The term pleochroism (more than the usual number of colours, many coloured) is frequently used generically instead of either dichromism or trichromism. Note that dichroism (pleochroism) is due to the fact that the absorption of linearly polarised light is a function of the polarisation direction, whereas colour due to birefringence (double refraction) is due to the retardation introduced by the refractive indices encountered by linearly polarised light."

Taken from "Colour and Optical properties of Material",by R.Tilley,2nd edition, published by Wiley,2011. READ WELL: "ON ROTATION" , which means changing angles when viewing the crystal , not one colour under reflected light vs another colour in transmitted light. Wake up buddy. Read what dichroism really is and depends on the DIRECTION of the polarisation. Yet as all vulgarizing books the author contradicts himself in the page dedicated to Lycurgus cup and in the chapter "colour due to scattering" he repeats the commonly admitted incorrect term that the glass is "dichroic" (pages 193-194) even though he demonstrates the glass shows two colours due to SCATTERING and not due to pleochroism. Well that's his problem and we'll see what happens in the 3rd 4rth or later revised editions (it is the 2nd I have). Still here is one excerpt for you: "The difference in colour between a typical ruby glass and the Lycurgus cup can be explained in terms of the relative amounts of scattering and absorption. The small particles which occur in gold sols, gold colloids and ruby glass are of the dimensions which exhibit high absorption and low scattering." (page 194) Yes, you are not hallucinating, he really wrote about the difference between TYPICAL RUBY GLASS and the Lycurgus cup... which implies the Lycurgus cup being of a NON typical ruby glass type, or else he wouldn't write "TYPICAL RUBY GLASS" . The one who failed the whole time is YOU, Johnbod, you go on making a selective reading of the sources, deciding that the Lycurgus cup is not a type of ruby glass -which is confirmed by all specialists even if they also call it a type of dichroic glass- . The problem I mentioned about the term "dichroic" is another subject. Start by reading the chapter in question and the associated wikipedia articles I mentioned. — Preceding unsigned comment added by 82.240.163.245 (talk) 06:34, 3 January 2014 (UTC) More textual proof that the glass from the Lycurgus cup is considered by some a type of (gold)ruby glass : "The Lycurgus cup. Hence, the first milestone in the history of gold ruby glass is a Roman opaque glass cup dated to the fourth century, the Lycurgus cup" Taken from page 8 of "Gold nanoparticles for physics, chemistry and biology" by C.Louis and O.Pluchery, 2012, Imperial College Press, 2012, ISBN 978-1-84816-806-0. Need more excerpts? We already have 4 up to now that confirm that the Lycurgus cup ,a lthough being coined as dichroic glass, is ALSO called a type of ruby glass. Here the authors go as far as saying it is gold ruby glass since without the gold particles, the other colloids would not produce the color change.

As I've said, ruby gold glass can be mentioned, but in accordance with what the sources say. You are still picking and choosing between sources based on your own interpretation of what is correct, blasting some & over-inflating and distorting others. With Freestone et al you somehow do both at the same time - his clear main term for the cup (dichroic) is described as inaccurate, outdated, wrong, vulgarizing, imprecise, unscrupulous & god knows what else, but his incidental references to ruby glass you pretend are his main characterization of the glass - they aren't. Several of the sources dealing with the cup don't mention ruby glass at all, but all mention dichroic. You need to accept they are right to use "dichroic glass" as the main descriptive term, and that it is incorrect and inadequate just to describe the Lycurgus Cup as "gold ruby glass" without mentioning "dichroic" at all, as your reverted edit tried to do. The cup does not meet the definition of "gold ruby glass" but can be considered as as an analagous type because of similarity between the chemical composition. And btw "coining" does not mean "to use as a descriptive term" but "to invent a new word". Given that there is a plethora of recent and scientific sources dealing directly with the cup there is no need to infringe WP:SYNTHESIS by using sources from other fields that don't mention the cup or even glass at all. Wikipedia articles are not WP:RELIABLE SOURCES. Johnbod (talk) 15:49, 3 January 2014 (UTC)

And we needn't take your last source very seriously, since it incorrectly describes the glass as "opaque" - if it was there would be no colour effect, would there? Johnbod (talk) 13:05, 6 January 2014 (UTC)

Intentional coloring of glass

This article gives a slightly different description of the production of the glass in the Lycurgus cup:
http://pubs.rsc.org/en/Content/ArticleLanding/2009/JM/b809646e
The cup is only discussed in the first paragraph (inc. pictures), but the authors describe intentional use of gold in glass:

The Romans formed these highly coloured objects by adding “for good luck” coins into the glass forming melt, these coins dissolved in the high temperature of the glass forming process and adventitiously formed alloyed nanoparticles embedded within the host bulk glass matrix to form a composite.

This varies somewhat from the current description in the article, which mostly implies that color properties arise from accidental/unknown inclusion of noble metals in the glass. It seems a stretch that the significant (and frankly wondrous) properties would be produced completely by accident. The authors in this case are chemists/nano scientists, and not archeologists. Unfortunately, there is no other reference given for the glass-making process.

ScottHW (talk) 01:08, 12 March 2014 (UTC)

That's a very different method from that all the other sources suggest. Would a gold coin in fact melt at glass-forming temperatures? The addition of even a single coin would be enough for a really massive quantity of glass, given the tiny quantities in the nanoparticles, and yet only a handful of pieces are known. Johnbod (talk) 04:41, 12 March 2014 (UTC)

I do realize that this is quite different that what is currently described in this article. That is why I wanted to bring it to attention, but since the article I referenced only describes the hypothesis superficially, I didn't want to add it to the article yet. I may still consider adding it, clearly described as an alternate hypothesis.
Gold would definitely melt and entirely dissolve at the working temperature of most blown glass. Gold Tm = ~1064°C, batch temperatures are routinely higher
http://www.gafferglassusa.com/index.php?route=information/information&information_id=7.
You are right that a small amount of metal would be sufficient to "treat" a large batch of glass, at least for forming embedded nanocrystals with optical effects. But I think the fact that few artifacts remain is not really any kind of proof that this isn't a reasonable hypothesis; many other factors will undoubtedly effect the existence of 1700 year old glass goblets of very high value.

ScottHW (talk) 02:53, 20 March 2014 (UTC)

Romans never put "gold coins" in a glass melt. It is an inaccurate description far from the truth: as the previous books -from which I've taken the refs- explain it clearly, it is highly probable that the only source for small amounts of gold was debris from goldsmith shop such as bits of gold foil along with the presence of gold salts in the same place as well as contamination with tools that had been in contact with gold powder.Whether it was intentional or not is not a scientific matter but a question of opinion and history: some may have done it "by chance" while others purposely produced coloured glass, as for the effect in the Lycurgus cup, since there are only very few gold-silver colloidal doped antique glasses and only in the state of fragments, it is even more difficult to decide what was the eaxct intention of the artisan. As for the gold coin to the melt myth, it suffices to read the chemical analysis of glasses made with either gold, silver or both. Minute amount measured in ppm are the cause of the colouring, whether it's intentional or not, and the mass equivalent of a few coins would have to be "dissolved" in a mass of melted glass so big it would be bigger than the whole neighbourhood and beyond. To get an idea, do a simple conversion from an estimate in volume of one roman gold coin to the equivalent mass in gold, then compare this amount to a reasonable estimate of a full batch of glass melt ( as used during the process of glasses similar to the lycrugus cup) and then compare this ratio with the ppm percentage of the actual amount of gold in the lycurgus glass. Coins being added are just an urban myth. It is the equivalent of saying that the domes of russian orthodox chruches are being made golden in appearance because someone poured molten gold on the said roof, when in fact artisans painstakingly flattened out gold with hammers to produce gold leaf then applied it with brushes. Similar beliefs such as "gold coins to produce cranberry glass" can be found concerning descriptions of antique and biblical monuments: some doors were said to be made of "solid gold". Yeah sure: archeological findings systematically proved that thin gold plates or foil were used instead, solid gold was only found in much smaller artefacts such as crowns, torcs, earings, hilts etc. Solid gold chariots, palaces, doors and whatnot belong to religion and myths, while gold coins added to melting glass belong to urban myths stemming from genuine attempts to (poorly) explain how colloidal gold and silver glasses were made in ancient roman times. Midas was the name of actual rulers of Phrygia, but does that make the mythological "Midas touch" real? It all comes down to putting myths and beliefs aside as well as innacurate descriptions made by people who didn't spend their time in scrupulous analysis but only wrote what they believed was true or wanted others to believe as such.— Preceding unsigned comment added by 82.240.163.245 (talk) 16:46, 16 April 2014 (UTC)

I agree - none of the more specialized sources echo "The Romans formed these highly coloured objects by adding “for good luck” coins into the glass forming melt,...". Johnbod (talk) 18:14, 16 April 2014 (UTC)

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Weight

The main article shows its size, on the top right area. I suggest to also add the weight, below the size. Right now I can not seem to find the weight of this cup at all int he main article, but it may be interesting for visitors to know how heavy the cup is. 2A02:8388:1641:8380:3AD5:47FF:FE18:CC7F (talk) 19:07, 23 February 2020 (UTC)

History

Right now there is not that much history in the main article. I understand that most of the history is lost (nobody made recordings I suppose), but perhaps we can still indirectly infer, e. g. who might have created the cup based on technique, and determine the age somehow. I think if links are used for the speculation then it could be added to the main article if it makes sense (and is based on these facts rather than merely speculation). Right now there is little to no information about WHO created it or WHERE it was created. 2A02:8388:1641:8380:DC5B:D810:7F56:116D (talk) 11:40, 21 November 2020 (UTC)

Have you actually read the article? Johnbod (talk) 13:45, 21 November 2020 (UTC)