Black Beauty Nickel?
0

9 posts in this topic

  • Member: Seasoned Veteran

So far as I know the "black beauty" nickels are exclusively Philadelphia coins from the late 50s. I've  not encountered others.

Link to comment
Share on other sites

It's nothing but a coin with a uniform black cupric oxide coating, created by heat such as holding a little above a gas flame. Absolutely no numismatic value so far as this poster is concerned.

Link to comment
Share on other sites

5 hours ago, RWB said:

It's nothing but a coin with a uniform black cupric oxide coating, created by heat such as holding a little above a gas flame. Absolutely no numismatic value so far as this poster is concerned.

So, I take it you do not hold to the "Improperly Annealed Planchet" explanation for the color of the "Black Beauty" nickels.

Edited by Just Bob
Link to comment
Share on other sites

Depends on the era and manner of planchet production. Surface oxidation of copper is the source of black "fire scale." A rolled strip cannot produce a completely black blank - the edge would be normal. Overheated blanks would be very unlikely because they go through the upsetting mill which normalizes the edge and would reveal normal metal due to scouring and scraping actions. (Occasional pieces might escape.) A blackened planchet would undergo the same mechanical and crystallographic deformations as any other planchet; again, this would likely reveal normal metal. (Cupric oxide from excess heat and oxygen during softening should produce an extremely thin coating - much thinner than on the current plated zinc 1-cent pieces.)

A black blank, planchet or coin would be prominent during cursory inspection.

One other note. The US Mint and companies providing coin planchets exclude oxygen from their annealing furnaces. If these blackened coins were produced as-is at a US Mint, they would be more likely to appear during the late 19th and first half of the 20th centuries when it was more difficult to exclude oxygen from annealing furnaces. Lastly, most US 5-cent planchets and  blanks were/are supplied by contractors. US Mints did not have the specialized resources to correctly anneal CuNi alloy on a large scale. Liberty nickel planchets were initially bought from Warthon in lots of 50,000 lbs.

The way to get a uniform, semi-glossy black surface is to heat a normal nickel just above a gas flame that has been properly adjusted - the flame will be blue and without soot. The flame will be approximately 1980 degrees Celsius and this temperature will cause rapid oxidation of surface copper.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
0