Can't advise anything about the glass as you ask. Not my field of interest in this type of glass really. Haven't come across any looking like this.
Re: The Medallion.
I've collected coins and medallions [true term for this piece], but not of this country or era. I have no interest in Service Medals, but same collectors rules apply.
Link provided comes up as a 404 error for me, but found this page using search terms of "St Anna mine"
https://www.bundesbank.de/Redaktion/EN/Standardartikel/Bundesbank/Coin_and_banknote_collection/medal_portraying_the_mining.html?submit=Search&searchIssued=0&templateQueryString=St+Anna+mine&searchArchive=0&withoutTeaser=trueThats a sizable medallion at 80.8mm diameter and 231g mass.
The web page does not state the alloy. If it's not a reproduction, due to low mintage it's value is far higher than pure silver if 999 grade [99.9%] anyway. Thats if it hasn't suffered wear or polish damage.
Very detailed die engraving on original specimens, even though rather large field to work on I must say. Nice.
DO NOT for any reason attempt any form of cleaning of coins. It will strip metal, detail and more so, huge value to a collector.
Not to offend, but Americans have had passion for cleaning coins through mechanical and chemical means for years. Someone before you has probably got to it and accordingly stripped detail and natural oxidised patina tone from it. Chemical agents to 'restore' it will only do further damage.
Again, DO NOT CLEAN COINS OR MEDAL etc.
You will eventually deeply regret doing so.
You assume it's reproduction? Why?
Does that diameter correspond to what is adhered to the glass?
Unfortunately the De.Bank web site doesn't specify thickness nor edge treatment [could be plain, reeded, embossed or engraved]
The images are good though and show details like rim on faces of the disc.
You say it has die stamped detail both sides.
This is not really something done for a piece intended for adhering to a glass like this.
Reputable mints that do reproductions would make it with a size difference or distinct modification to design like modern production date or makers mark, or omission of a face, to prevent it's use as forgery.
First step would be to check size.
DO NOT attempt to remove by mechanical means.
From what you say I'm assuming you see it has been glued to glass?
It would not have been fused to molten glass. The heat involved would have oxidised surface and silver does not bond to glass well. Copper does.
What is the appearance of the adhesive used? Clear epoxy type stuff? Might have gone a yellow colour by now?
It appears to be a glue best bet would be soaking in serious solvent to slowly dissolve whats there. Again, do not leaver it off in any way. Silver is soft, it will scratch with even tissue paper.
If clearly a reproduction medal. it may be a lower class metal like pewter or pot metal alloy of aluminium... or a better copy would be in a silver alloy... perhaps, but not likely due to bullion prices 50% silver, lucky to be 80% or 92.5%.
A coin dealer in Germany or maybe even America may be able to advise if there have been any contemporary reproductions of this medallion. They will also have an interest in Service Medals and Medallions. Submit good quality images for initial appraisal. DO NOT accept a Dealers value of it nor coins. They profit seek and the difference between 'buy' and 'sell' prices will disgust you.
If there is no known history of copies [and in any case for now] consider it would be far more valuable than the glass it's mounted in or the combination of glass/medallion.
It would require detailed 'in hand' examination of the item to determine 'grade' [how damaged it has suffered] and accordingly value if indications are it is indeed original minted. Age and Mintage of less than 100 makes it "excessively rare".
A jeweller would be able to give an idea of metal and purity BUT thats done via acid test so make sure they don't do so in conspicuous location.
DO NOT do this if initial indications are it could be original.
If in poor condition and reproduction of silver alloy... the bullion value can be calculated from 'spot price' of silver factoring in alloy [say 50%] and mass of 231g.
If you post further images of Med. here make sure you use the camera on macro setting and get in real close with good diffused light. Sometimes better images can be obtained by high resolution scan [like you would a photo or document].
In terms of glass, photo of base showing characteristics you describe, the rim and the glass framing the metal would be most helpful for further assessment.
Sizes also help.
Topic: Vintage Glass Tumbler with embedded medal (Read 1457 times)
