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 Replies: 24 / Views: 2,863 |
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Valued Member
 United States
168 Posts |
Quote:
The flow lines are very clear What exactly are flow lines? Are flow lines depicted in my second picture? Thanks. I also found this site helpful but I don't speak Spanish (google translator is terrible)  http://translate.google.com/transla...sorillo.com/Edited by w00zi
06/10/2012 8:27 pm
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Bedrock of the Community
United States
10045 Posts |
On the last pic you posted, I think the raised ridges going left are "flow lines"
Outward metal movement from the strike wears ridges into the die--correct me if this is inaccurate.
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Pillar of the Community
3352 Posts |
Really? ... Ummm gawd, I'm pretty sure that if you zoom-in close enough on "anything", then it's gonna look kinda like something nasty from one of your college parties!!? However, those are certainly amazing photos, so "keep-up the good work in the genetics thang" ... => Every now and then I miss my college-daze ... then I wake-up and realize that I'm burning hotter now than I was then! ... => what the heck is retirement gonna be like!!   |
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Moderator
 United States
23731 Posts |
I remember the coin and that I had some concerns about the brown color between the letters. I believe the coin is from the period but maybe a fouree.
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Valued Member
United States
168 Posts |
Thanks for the info! and I believe the green deposits are malachite (please correct me if I am wrong). The green deposits are not visible by the naked eye. And are fouree usually silver plated? If so I can easily do a density test to check the metal composition.
Edited by w00zi
06/10/2012 9:22 pm
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Bedrock of the Community
Australia
21788 Posts |
Very few official silver coins of Caracalla were plated, but this appears to be one of them.
The corrosion products of the substrate metal suggest a copper (alloy) core.
Interesting.
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Moderator
United States
23731 Posts |
Fouree have a thin silver layer over a base metal core.
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Pillar of the Community
United States
1549 Posts |
I see nothing consistent with the coin being fourree but the only way to be sure is to cut the coin in half and I wouldn't suggest that. What we see as corrosion products can also be explained by the coin being under 50% silver as are most Caracalla denarii and/or by being hoarded with copper coins. Fourrees tend to wear in certain ways and peel in regions not seen on this one.
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Valued Member
United States
168 Posts |
Quote:
under 50% silver Thanks for the info. dougsmit! So are these coins susceptible to bronze disease? |
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Pillar of the Community
United States
1316 Posts |
Our modern coin's are not heated when struck, the pressure put to the die's makes the metal flow like a liquid. Filling in all areas of the die. If highly polished and struck many times will give the cameo look as a proof coin. These coin's were heated red hot, as they cooling off were struck leaving flow marks and a slip look to the letters as they pulled it a part. As they were making these coin as fast as they could, the temp was always different. Leaving each coin with a little different surface. also maybe in this case, the metal might have had slag or other metal's not melted ,flowing to the top of the coin and now are rusting in those place's, they sure weren't .999 fine, just a thought...  |
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Pillar of the Community
United States
1549 Posts |
I have a rare denarius of Julia Domna from Alexandria that had BD but it was a lot lower grade than 50%. I don't know when the threshold of the problem is.
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Bedrock of the Community
Australia
21788 Posts |
Dougsmit: Is it possible for you to post a picture of a fouree with corrosion. I guess most of us could learn a little, certainly me.
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Valued Member
United States
168 Posts |
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. Fourrees tend to wear in certain ways and peel in regions sel_691, an ebay search for fouree will reveal many examples with the peeling dougsmit describes. I also feel my coin is not a fouree (I am certain the coin is not plated). |
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Pillar of the Community
United States
1549 Posts |
I do not have a photo of bronze disease having always rushed to treat when I saw it and not bought coins with it if I saw it first. The image below is from my fourree pages and shows stable green (hard) corrosion in a broken edge of a Julia Domna denarius. My pages have several other fourree photos that could be educational to anyone who cares to look.  whole coin:  I just checked the (solid but low grade silver) denarius that had BD (I keep that one at home for regular inspection!) and am happy to report that it shows no sign of relapse so I can't take a photo. I do believe that half of the times people on the list diagnose BD they are actually seeing stable corrosion but it is better to be safe than sorry and I usually stay away from suspicious coins on the theory that they are more trouble than they are worth. |
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Valued Member
United States
168 Posts |
Thanks for the info dougsmit! I am curious if anyone else here has an example of a coin with bright orange cuprite (copper2 oxide). Cuprite in nature can be found in the red to orange range but I have yet to find another example of an ancient coin with orange cuprite.
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Replies: 24 / Views: 2,863 |
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Posted 06/10/2012 8:06 pm
