what metal wears faster.....silver or copper?

ILikeMercs · February 27, 2006 3:04PM

I was sitting here reading another thread and Stewart said how he'd like the 1877 IHC Elvis' daughter has or had. I see the mintage is 852k as opposed to the 16-D merc whose mintage is 264k. I got to wondering why, with 3.75:1 mintage, the IHC goes for the same approximate price in worn grades. Total population is 5:1 for the penny. Anyway, all that BS aside, it got me to thinking....which metal wears down faster, copper or silver?..............

solid · February 27, 2006 3:09PM

Isn't one of the reasons for alloying 90% silver with 10% copper to "harden" the silver, making it wear slower?

As far as pricing on the 1877 IHC vs 16-D Merc goes, it would be a function of supply and demand. I don't
know which is more in demand, but would guess the survival rate of the cent to be MUCH lower. Aren't there
more 16-D Mercs in existance now than when they were first minted? Or is the the 09-S VDB?

Ken

michael · February 27, 2006 3:11PM

silver

coppercoins · February 27, 2006 3:13PM

Silver is naturally softer, so it would wear faster with all else being equal.

ILikeMercs · February 27, 2006 3:15PM

thanks...that's what logic was telling me, that's why I threw the ratios in.....I just wanted other opinions because I have no idea where to find out for a fact. I guess it's somewhere out on the big ole internet, but you guys know your stuff and it's easier to just ask................

tjkillian · February 27, 2006 9:49PM

The value of coins is a function of supply and demand. There are many lower mintage coins that are significantly cheaper than either the 1916-D or 1877 indian cent.

Tom

slipgate · February 27, 2006 10:19PM

coin silver (90/10) has a density of .373 and Copper has a density of .323, the lower the number, the harder the metal, so copper is harder, but not by much.

stainless steel - .285
copper - .323
coin silver - .373
fine silver - .379
24k gold - .698
platinum - .775

carl · February 27, 2006 10:45PM

Ahh, slipgate is reading a chem book I think. Very true as to what he said. However, slipgate, remember there are numerous grades of stainless steel and the density varies with the metalic consistensy. All steels are a mixture of metals and not an element that is consistant in atomic or molecular structure. In reality even the same grade of some stainless steels are different due to impurities in the batch at the mills. Coin silver may vary due to denomination and date. However, your basic findings are accurate.
As to the original question though, wearing of a metal depends so much as to it's invironment. Even the material of a pocket in your pants where a coin is carried may be different enough from others to make a wear difference.

morganbarber · February 28, 2006 1:19AM

Silver "wears" faster, but is pretty stable. Every detectorist knows that copper corrodes and turns to yuck. Another key to survivorship is whether or not copper coins are ever melted to make more coins. Many great silver date/mintmarks were melted to create common date coins. I don't know the answer as to whether copper is ever melted for new coinage, but I hope someone who does will reply.

Cladiator · February 28, 2006 1:26AM

<< <i>coin silver (90/10) has a density of .373 and Copper has a density of .323, the lower the number, the harder the metal, so copper is harder, but not by much.

stainless steel - .285
copper - .323
coin silver - .373
fine silver - .379
24k gold - .698
platinum - .775 >>

That would make platinum uber soft. I know I've heard in multiple places that platinum was a very dense and hard metal. Did I hear wrong?

cladking · February 28, 2006 1:54AM

There would be some overlap in the hardness of silver and copper alloys as used for coinage.

Silver is the softer metal but alloys are used to make it much harder. Wear is a function not
only of hardness but also of weight. Most of the wear to which any coin is subjected is due
to the force applied by its weight or the momentum of which weight is a determining factor.

Some issues are melted and some aren't. Worldwide there is more tendency for mass melts
to occur with base metal coinage and silver tends to be destroyed only in minor melts. Few
US base metal coins have been destroyed systematically but relativelty small amounts of sil-
ver have disappeared this way except for the dollars melted in 1918.

There is not a great deal of correlation between hardness and density.

Conder101 · February 28, 2006 2:59AM

<< <i>That would make platinum uber soft. I know I've heard in multiple places that platinum was a very dense and hard metal. Did I hear wrong? >>

In its pure state platinum IS very soft and mallable. But when alloyed it becomes very hard and difficult to work.

<< <i>There is not a great deal of correlation between hardness and density. >>

I suspect they may be using he wrong term, or this is some definition of "Density" that I am not familiar with. The numbers they give for these "densities" are nothing like the figures for density that I know for these metals. Normally density is used to mean mass per unit of volume as in pounds per cubic foot etc. Since you can choose any units you want to use to measure the mass, and whatever unit volume you want, the final number can be anything. And if the units aren't stated then the number is meaningless. When the mass is measured in grams and the unit of volume is a cubic centimeter then the density equals the same number as the specific gravity of the material. and it is also the most commonly seen figure used when someone is talking about the density of a material. Slipgates figures seem to me to be the reciprical of the hardness of the material as measured on the Rockwell(?) hardness scale (1 - 10 wih talc the softest and diamond the hardest.)

JDelage · February 28, 2006 6:26AM

Nearly all metals can have different hardness depending on their condition. Copper, gold, silver, etc, can be hardened by "working" them. I don't know if striking it is enough to harden it fully, but I'd guess that circulated copper - having spent much time dinging into other coins - is much harder than when mint.

Obviously, steel can also be in a soft state (annealed) or a hard state (after heat treatment), and pretty much anywhere in between. It results in changes in volume, and therefore density (that's why Japanese swords are curved: the edge was quenched to be hard and has expanded, while the back is kept in a soft state).

Jdurg · February 28, 2006 8:34AM

<< <i>coin silver (90/10) has a density of .373 and Copper has a density of .323, the lower the number, the harder the metal, so copper is harder, but not by much.

stainless steel - .285
copper - .323
coin silver - .373
fine silver - .379
24k gold - .698
platinum - .775 >>

That's not exactly true. Lithium and Sodium metal are VERY "not dense" yet they are two of the softest metals in existance. (Li is about 0.57 g/mL and Sodium is around 0.97 g/mL). On the other hand, Uranium metal is nearly as dense as gold yet is one of the hardest metals out there. In reality, there is no correlation between hardness and density.

As you can see in the image below, the "hardness" of an element (As defined by MegaNewtons per square meter) really has no visible trends.

Density, meanwhile, does have a trend that can be seen. As you move down a group, density generally increases. As you move across a period, density increases until you reach the center of the period. Then it decreases once more. So the denser metals are located in the lower center of the periodic table. However, if you superimpose those images on top of each other you really don't see any type of association.

what metal wears faster.....silver or copper?

Comments

Leave a Comment