Gules is within the scope of the Heraldry and vexillology WikiProject, a collaborative effort to improve Wikipedia's coverage of heraldry and vexillology. If you would like to participate, you can visit the project page, where you can join the project and see a list of open tasks.
I agree that it's strange. If you look at Sable (heraldry), its planet is Saturn, but it is assigned both the expected lead and the iron expected for this article. Furthermore, if you look at Azure, it does not mention a metal, though one would expect copper. From looking at the histories, it appears that 126.96.36.199 was responsible for the addition of what each tincture represents. Given the plausible nature of the edits, I hesitate to change alter them without finding an authoratative source. David H. Flint 08:43, 20 February 2007 (UTC)
There was a Renaissance heraldic system of sometimes using planetary names (or names of gemstones) as an alternative way of indicating colors -- see http://pages.ripco.net/~clevin/gemarms.html and http://www.levity.com/alchemy/hermhera.html for websites which I pulled up through searching just now (but which seem reasonably well-documented), and http://www.heraldsnet.org/saitou/parker/Jpglosst.htm at "Tincture" for an online version of an 1894 book which I've seen physically at the University library. However, I'm not sure where all the other stuff comes from, or whether it could be documented. Once you assign the colors to planets, then of course the "alchemical" assignments of metals to planets could be used to assign metals to colors, but whether practitioners of heraldry actually ever did this is another matter... Note that all three of the above sites, and also http://historymedren.about.com/od/pimbley/a/pim_t_2.htm , associate Venus with Emerald/Vert, contrary to what is said on the Vert article... AnonMoos 11:58, 20 February 2007 (UTC)
Having looked at all the sources you found, they are all either real books, or well researched. I made a table of what each of proposes as the mapping between tinctures and planets/metals/gemstones. They are unanimous in their mappnigs between tinctures and planets/gemstones. Though only one source talks about which metals map to which colors, it seems that these metals are a straight application of the alchemical association of planets. As you said, it raises the question as to whether practitioners of heraldry made these associations, and all the others that are listed.
From these sources given though, the following associations are at least correct, if not made by practitioners of heraldry
I think it likely that most of the associations given are an application of alchemy/astrology or hermetic beliefs. Practitioners of heraldry probably did not make these explicit associations. I propose removing all associations except for planet and gemstone, according to the table given. I think the association with metal should be removed too since the source which talks of that assocation seems to be talking of the parallel syncretism of hermetic and heraldric imagery, and it is not clear that to me that metal association is made in heraldry as it is in hermeticism. David H. Flint 03:10, 21 February 2007 (UTC)
Thanks for making up the table; I was thinking of doing it, but you beat me to it... Should probably take the general discussion to Talk:Tincture (heraldry) now -- I'll post something there. AnonMoos 03:26, 21 February 2007 (UTC)
Posted to Talk:Tincture (heraldry), see there. If no one replies or objects in the next few days, it will probably be OK to go ahead and make the canges. AnonMoos 03:54, 21 February 2007 (UTC)
P.S. The associations between yellow and gold, and between white and silver, are of course naturally heraldic -- it's only the other five associations between metals and colors that may be more occultistic than heraldic... AnonMoos 08:34, 21 February 2007 (UTC)