Anyone know if the mint produced any foreign coins in 1988 that weights around 4.9 g that is about t

LALASD4

Anyone know if the mint produced any foreign coins in 1988 that weights around 4.9 g that is about the size of a nickel but thicker and is not (Copper - 75% Nickel - 25%) ?

Conder101

Other than the Iceland 2 Kroner for the Leaf Ericson Milennium set the mint has not struck any forein coins since 1984. A 4.9 gram weight would be within the tolerace range for a nickel.

LALASD4

Other than the Iceland 2 Kroner for the Leaf Ericson Milennium set the mint has not struck any forein coins since 1984.

Then it cannot be a foriegn coin. But it is 35% thicker than a normal nickel yet lighter.

Conder101

35% thicker yet slightl underweight? Interesting. I'd be curious to know what the specific gravity is. What does it appear to be made of?

LALASD4

Not sure, maybe alumium or other lighter metal?

Conder101

Aluminum would be too light, an Al alloy maybe. An iron alloy would work, possibly a stainless steel composition would work but where would the plabchet have come from? The mint does it's own blanking of the nickel strip so it shouldn't be possible for it to have come in from outside.

errormaven

4.9 grams is within acceptable tolerances for nickels. A thick appearance on edge could be due to finning of the rim or a strong strike combined with abnormally deep rim gutters.

It's highly unlikely that it's a foreign planchet.

If you suspect the coin's density is abnormally low, you'd have to verify it with a specific gravity test.

--Mike Diamond

cladking

It's easy enough to get specific gravity if you have a good scale. Just divide the difference of the
weight of the coin in water and it's weight in air into its weight in air.

errormaven

Doing SG tests is simple in principle and difficult in practice. You need a balance that's accurate to at least the nearest 0.01g. You need the right sort of cradle for the coin, one that's denser than water and that won't trap air. You've got to make sure there are no air bubbles trapped beneath or clinging to the coin. You need a balance that suspends the object being weighed. A platform balance is much more difficult to use in this procedure. Even a measurement error of .02g is enough to blow the result. Repeated measurements are a must. A comparison sample is a must (don't rely entirely on published values). SG does vary among normal coins, so your result must be beyond the normal range of variation.

LALASD4

It is not finning.

I need to go work for a lab.

Conder101

Errormaven is right that it a SG test is a little demanding but if you do it a few times it becomes fairly easy to do. It's just a matter of practice like most everything else.