1859 Penny How Yellow Is Yellow

Nice coins, even if the one is yellow. LOL. Certainly makes it different. :)

That is very interesting Bosox. There's no decent published study on this that I could find. I need a sample of 100 units to even give enough of an indication that it's even worth investigating further. I've seen higher lead concentrations though, certainly more than trace picked up from moving down the channels during founding. There is some minor sampling of other Heaton planchets and we know they kept lead stock around and that it was a cheap filler.

The dealer (who I know and respect) who submitted it told me it was submitted with a spectro result of 85% copper. I suspect PCGS did their own spectro verification, but don't know for sure since I did not submit it.

Spectrographic analysis is a blanket term that usually involves destructive testing. The advances in spectrographic analysis have all surrounded the quantity of material needed being decreased, the available reagents becoming more targeted to the likely alloy etc... Even rapid high tech machinery simply vapourises a sample with a laser in a chamber with inert gas so that it can be analyzed.

The point I suppose is you can't just look at an alloy and figure out what it is, somewhere down the line whether you use X-ray, infrared or visible light etc you need a small destructed sample.

This is all high tech of course, there are still old fashioned methods that involve basic chemistry you can do in primitive lab conditions, much like portable assay kits used in gold scrap dealing etc...

@biokemist16 Does that wink mean you have an XGT 5000 at home that you rent? :p

Yeah I know there are other devices, I'm sticking to things I've typically found in QA labs but like everything once you retire - your knowledge base can drift out of date rapidly. Mine has.

Point of fact thought, I don't see a TPG needing this to identify a brass coin. The colour really is a dead giveaway.

Nope, I do not have access to an XRF but BadThad does use one is his line of work. Thanks for listing you cost bosox, I figured $50-100 but that was only a best guess on my part.

When I did the tests, I posted about it on another site. Here are the more precise results that I posted:


Coin #1 - 1859 cent in Very Fine - weighes 4.31 grams - 94.37% copper, 1.13% zinc, 4.50% tin.

Coin #2 - 1859 cent in Almost Uncirculated - weighs 4.36 grams - 94.91% copper, 0.72% zinc, 0.17% lead, 4.20% tin.

Obviously the composition of both coins is quite close to the nominal 95% copper, 4% tin, and 1% zinc specified for the issue. The melting room at Heaton got it right on these two. Given the weights of the coins, the rolling mill operator did not. He rolled the bars too thin.