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 Replies: 9 / Views: 1,763 |
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Valued Member
United States
148 Posts |
I found this Sacagawea coin at the bank. The edging is weird as it looks like 2 different metals together. Here are some horrible pics with my phone. None of my other dollar coins look like this. Just thought I would post.    Edited by ilzho
07/03/2012 10:09 pm
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Pillar of the Community
United States
4132 Posts |
It's normal. Brass bucks are brass on the outside bonded to a pure copper center, similar to quarters, dimes and half dollars. It's not usually very noticeable when they're fresh and new because the bright copper color doesn't contrast strongly with the brass.
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Pillar of the Community
United States
1699 Posts |
I'd also like to add that some of these native american and Presidential dollars are sometimes struck without one of these outer layers. Although less common and less noticable than dimes and quarters struck without a clad layer, they do happen. Edited by ErrorCoins222
07/03/2012 11:05 pm
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Pillar of the Community
United States
965 Posts |
 All modern dollar coins are clad, just like all modern (1965-present) circulation dimes, quarters, & halves. |
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Pillar of the Community
United States
1195 Posts |
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Pillar of the Community
United States
1027 Posts |
Modern dollars are not really brass at all, they are 88.5% copper, 6% zinc, 3.5% manganese, and 2% nickel. That is composed of a cladding of manganese BRONZE (77% copper, 12% zinc, 7% manganese, and 4% nickel) over a solid copper core. As you can tell from the cladding and total percentages, the cladding is half of the total coin, which is a 1/4 - 1/2 - 1/4 sandwich.
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Bedrock of the Community
United States
17884 Posts |
It is a brass, to be bronze the alloy has to contain tin. A copper and zinc alloy with no tin is a brass. In this case it is called a Manganese brass because manganese is the next greatest element by weight in the alloy.
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Pillar of the Community
United States
1027 Posts |
It is the mint that calls it manganese bronze, and tin in not a requirement for a bronze. Other elements can substitute for the tin. The very first bronze did not contain tin at all, it was composed of copper and arsenic. Bronze is, after an imprecise term as Wikipedia says and "modern museum and scholarly descriptions of older objects increasingly use the more cautious and inclusive term "copper alloy" instead". In reality, brass and bronze are interchangeable, since the alloys vary and cross over so much and have changed so much over time. When the alloy is composed of only copper and zinc or only copper and tin, the distinction is more clear but when other elements are in the mix it gets quickly muddied, and historically these mixes of numerous metals (with copper as the primary) have been referred to as bronzes, even if no tin was present (and even if zinc was). From what I gathered in a quick search of metal alloy suppliers, they refer to alloys that contain only copper and zinc as brasses, and if any other elements are present they refer to them as bronzes.
Edited by clairhardesty
07/05/2012 5:01 pm
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Moderator
 Australia
16826 Posts |
Quote:
It is the mint that calls it manganese bronze... "modern museum and scholarly descriptions of older objects increasingly use the more cautious and inclusive term "copper alloy" instead". In reality, brass and bronze are interchangeable... It's all just semantics; the Mint chose to call its new dollar coin alloy a "bronze" rather than a "brass", because of the negative connotations the word "brass" has acquired in a monetary context, meaning "cheap" or "worthless". Personally, I distinguish "brass" and "bronze" by colour. If it's yellowish, I call it "brass". If it's more coppery orange-like, I call it "bronze". Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
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Pillar of the Community
United States
2295 Posts |
I'm surprised to hear brass is considered to be cheap. I've always heard that brass is expensive.
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Replies: 9 / Views: 1,763 |
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Posted 07/03/2012 11:04 pm
