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Coin Metal Finishes


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I've noticed there's a lot of coins that have metals/finishes that look alike and I was wondering if they are indeed the same or if they are actually different.


For instance the "silver" coins that I've noticed can be called: Silver, Pewter, Nickel or Chrome. Looking at CoinsAndPins.com they actually use the metals they describe. But what about Pewter - is it ever used or are they one of the other metals/finishes listed? (example: the GeoWoodStock 3 coin is listed as Pewter)


My other question is, what is Gun Black finish, is it the same as Black Nickel? or is they 2 seperate materials/finishes.


Are there any manufacturing experts out there / someone who's been through the process who knows?




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My guess is that some of the finishes are the same, but called different things by diffrent companies.


For example, ever try to buy a new mattress (I hope so, if not - blech!).

The same matress is sold to different companies, but named different things so you never realyl can get an apples-to-apples comparison.


For instance, I've seen a few finishes mentioned recently that I'd never heard of before like "misty gold".

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The thing I sometimes wonder about is what is the base metal of the coin? and does it affect the tone of the final product?

My understanding,( perhaps wrong??) is that many coins are actually stamped in one metal then plated, polished, painted/coated, and numbered. I thought many used bronze as the base, but the last couple coins i've drilled holes in (getting ready to release) were actually some sort of grayish metal.

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Some companies call metal types by the color of the metal instead of what it is actually made from. If it is a 'silvery' color, then they call it silver. If it is gold-ish, then they call it gold. You will have to see samples from the different companies to really tell the difference, and even then it can be difficult. Sometimes asking about the specifics will reveal what it really is. Of course it is a little easier for me since I have seen them all for many years, so I hope I can break it down in a decent way. Also take into consideration that many factories and brokers do their work differently, so the below info is not 100%. If you feel that I am wrong with the below information then there is no need to correct me on it since I already know the variances, but I don't want to spend 3 hours typing out all the possible differences.


Here are some of the differences:


Base metals:

- Pewter is a base metal of a coin. It is a poor metal to make a coin from since it is prone to pitting, but it is relatively inexpensive and can make for affordable coins.

- Zinc is a better base metal to use than pewter, but it is very light and therefore feels cheap. It also requires the raised lines to be thicker and does not render detail very well. It costs less than pewter, but does not show as many blemishes as pewter.

- Iron costs more than pewter and is heavier. It weighs very close to brass. It is a down-grade from brass since it will show a few more surface blemishes than brass, but will cost less than brass. Its major flaws are that it is prone to production problems since it has a tendency to crack dies (due to being a harder metal), and can develop a light surface rust before the plating process if the factory air is real humid at that time. This light corrosion will more than likely not show up to the end user, except in the case of putting them into caches where the plating might show those weaknesses over a long time. It can also corrode within the etchings if the coin is circulated and gets damp.

- Brass is the best metal to use for logo type coins (logo coins are really what geocoins are). It is heavier than most metal used and shows sharper details with less flaws.

- Very few companies use bronze. Bronze is used more for acid etching.


- "Merlin brass" is somewhat of a refined brass and only used by companies similar to the Northwest Territorial Mint. They use it to make proof-like coins, but it still oxidizes just as easily as regular brass. In the above examples, I used them in reference to having the metals plated which can provide some corrosion protection. In the case of proof-like coins, they are not plated and therefore subject to the typical corrosion of the base metal.



- Silver to us, and a few other companies, is silver; but to many other companies it is a plating comprised of several metals to make a simulated silver that looks…simulated. A real silver finish will tarnish unless it is epoxy coated, and even then it can show some tarnishing if the factory was humid before the epoxy coating is applied. It is not used very often since it is very bright which can obscure the detail of the design.

- Nickel is darker colored plating that is durable and will show details much better than silver. It is the best of the silvery looking platings.

- Chrome is a very dark finish and can make a coin look dirty. It can also flake easily if not applied just right.

- Rhodium looks like an in-between color of chrome and nickel. It is not durable and not recommended.

- Black nickel is mostly a black color. It is also not a very durable finish. It will show wear only after short time of handling, but lots of people like the look of this finish.


Some people will refer to pewter (and a few other finishes) as a color of a coin finish. It has been used in two ways:

1. It is usually actually the pewter metal you are looking at and no plating has been applied. Only a very thin coat of clear jeweler's enamel is on the coin to protect it from corrosion. It is used for pewter coins that have an antique finish. Pewter does not polish well, so you won't see that.

2. It is used to name the color of the plating finish since that is what so many people in the 80s and 90s called it when the military would get their coins made in places like Korea. They would say to the broker "I want a pewter finish", which meant "antique bronze" colored finish.


In the case of the Geocache America coin, you are seeing the brass base metal with antiquing and a light clear coat. In the case of many other geocoins, you are seeing the plating over the base metal, except most antique pewter coins.


Mostly now the companies have started calling them what they really are except the fake finishes of silver and gold. You will have to ask them to make sure.

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Thank you Aaron for this disambiguation. I read something in another post bagging the greenman coin insert which mentioned it is made of "merlin brass alloy". it is nice to know it is a valid numismatic term (and why it is such a lovely coin.)


Could you further explain how to clean a geocoin? I picked up a travelling plain brass coin which had started to pit. It was travelling in a velvet bag. A friend had sealed his plastic bags off with tape but regretted it and wanted poeple to be able to remove and handle them.

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Vaguely related to this, but worth noting for people who are thinking about this topic...


When I went to get my first coin done, I sent email to 5 coin minters asking a few questions, one of which was for a metallurgical description of their coins (what metals they use, if an alloy, the composition of the alloy). This was important to me because I wanted a certain heft to the coin, and it had to be made of something that would have a chance of surviving outside in a geocache in Canada (so iron/steel would be out of the question), and I didn't want them to be poisonous (so lead or lead-based pewter* would be out of the question)


I actually thought it would have been easy to get 5 detailed replies, but I only got two answers with the descriptions I asked for, and two others that basically said "huh?"


As you might imagine, I went with one of the two that provided good information on the metal content of their coins.


In any case, I think it's a great question to ask of someone who is going to produce these things for you, and you should be sure you choose a metal/alloy that will meet your expectations and requirements.


The same thing applies for coin finishes.



* in the last few years, people have generally stopped making pewter with lead and substituted other heavy, but less poisonous metal.

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