Gold Coin Purity Question

Is there a difference in the purity of gold between coins minted within the last 10 years vs coins minted 100+ years ago?

 

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Depends on the coin. Most old circulating coins were 900 gold. Most recent coins are bullion coins - 999 gold

 

I have a red book. Thanks for the suggestion anyway.

 

Reason I ask on here is to make conversation and share thoughts with others. Life wouldn't be as fun if you ran to books or Google search for every question you have. Besides, there's only so much you can learn from them.

 

Good question. Also, how about the consistency/precision/accuracy of the assays, then v now?

 

I thought about that also. I wonder how consistent the purity was back then versus now. I'm sure with today's technology the purity is very accurate and precise - within thousandths of one another.

 

Today's technology has little to do with it. The ancient Greeks and Romans were producing coins of extremely high fineness, much finer than the 90% silver and gold of US circulating issues. Fineness isn't so much a matter of technology as of choice.

 

Technology has everything to do with the precision and consistency of the fineness. Yes they were making gold coins back in the Roman days with fineness of 90% or greater, but that's not the question. Was the precision and acurracy (aka consistency) that of recent coins is the question. Todays variance is almost none existant. I would imagine any variances in fineness today are within .9999. For example .99998 vs .99997. I can't imagine Romans having that consistency with primitive tools. So technology does have something to do with it.

 

What I should have said is that fineness in recent history isn't so much a question of technology as of choice. The Romans may not have been able to refine metals to .99999 purity, but certainly .999.

 

It's interesting and amazing to read how capable we (humans) were a thousand years ago given the primitive tools we had, but you cannot convince me that they were more capable then we are today. Sure technology can create laziness and oversight errors since we rely on it so much, but if used properly, the products resulting from todays technology blow ancient products out of the water.

 

This may be of interest:

http://en.wikipedia.org/wiki/Gold_parting

 

Yes, and how it was done is quite intriguing, but I'll give someone else a chance to post it, if they know.

There's also the aspect that for monetary exchange, .999 fine was simply good enough to be called pure, whether silver or gold. A merchant wasn't going to haggle with you if your coin was .9998 fine, even if he could have detected it.

 

Relevant...

https://www.cointalk.com/threads/ancients-the-first-official-coin.251238/

 

This thread has had some very informative posts. I, for one, have learned a few interesting things. Things you don't find in a red book. Right, Ed?

 

Well, I never really asked whether they could refine to .999 (only asked what difference between then and now), but I agree that it is amazing the stuff they were able to accomplish with what they had at their disposal. You could argue it is more impressive than some of the things done today (after adjusting for the technology available). I suppose it was necessary for everyone (from shop owners to service providors) to be able to verify purity quickly before accepting payment. Nowadays that isn't as necessary so it explains why the common person doesn't, or know how to.

 

The assaying method Doug was referring to is the use of touchstones. Wiki has a brief article here.

A more detailed analysis can be found in this pdf.