Zcela po zásluze přesunuto na hlavní stranu, jen bohužel zmizely komentáře....
Takže - výtečná práce, Milane 
Buttons with polished gold - analysis
Categories: Finds and rescue research in the Czech Republic
I got into a discussion on hunters about these buttons where there were more opinions than facts and I as a person using statistics don't like that :)
A number of people claim that these buttons are made of copper, brass, that there was iron on the protrusions, maybe zinc, ... something. So I decided to analyze the buttons I own and share the results. So that in the future we can learn something and in turn disprove the various legends that may have arisen, so how is it really?
I have taken 10 pieces of buttons for testing, which could be described as the type "with polished gold". These buttons were then subjected to a material analysis of both the body and the protrusions, which were supposed to contain other material.
Result:
analysis of the button body - in all cases the button was made of brass (combination of copper and zinc). If the knob looks like copper, it is usually because the zinc has broken down on the surface of the knob and copper remains, but the body of the knob is made of brass
the protrusions on the button - the analysis confirmed that the protrusions that are preserved and not worn out always have the same material = iron. So no zinc, white bronze, silver, .... gold. If I found only brass on the knobs, it was because the surface of the knob was so worn that nothing was left of the knobs. So I did an analysis of the material under the lugs and there is a trace amount of gold. So even though we can't see it, the magnet is no longer reacting, some trace amount of iron can be found with a little luck.
Period of use - we can classify these buttons quite accurately, we know that they were certainly in use between 1750 and 1800. I attach a photo of this kind of buttons made of coloured plastic and made for the emperor during his visit to Banska Stiavnica in 1751 (Slovakia - Banska Stiavnica - silver mining). As we notice, the button had a surface treatment with gold plating.
PS: I am attaching photos from the analysis of the material, I did not put all of them, because it would be a bit too clear
And that's all ...
End of voting! :)
Milan
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Komentáře přesunout nejdou. S Milanem jsem domluvený, že takto zajímavé věci budeme dávat na hlavní. 
Krásná práce. Ten jeden knoflík (prostřední řada, první zleva) je rybářský.
Pěkná práce badatelská a rozhodně zajímavé 👍🏻😉