Comments on numismatic terms

[Figleaf]

Please comment on existing terms and explanations and propose additional terms for the numismatic terms thread here. Additional translations are very welcome also.

Peter

[a3v1]

Peter, nowadays' coins always are fiduciary coins. So the authority that has issued a coin and guarantees its nominal value is of paramount importance.
So that's why the side of any modern coin showing the nation of issue always is the obverse.
Regards,
a3v1

[Figleaf]

Comment received from aurelianus in Dutch (my translation) on:

Verdigris   A light to blue green powdery layer on bronze coins, caused by a chemical reaction of copper(I)chloride (CuCl). When left untreated, verdigris will destroy a coin.

Verdigris is the trivial name of copper(II)acetate. This is not the same as copper(I)chloride and it is not an active constituant in bronze rot.

My questions: 1) What is verdigris in English? 2) What is the word for the effect I mention in the description?

Peter

[Figleaf]

No answers to my questions above? Not even opinions? The word verdigris is correct usage in French, my professional translater daughter tells me. Yes indeed, more French translations will be added to the numismatic terms.

Peter

[Figleaf]

Peter, nowadays' coins always are fiduciary coins. So the authority that has issued a coin and guarantees its nominal value is of paramount importance.
So that's why the side of any modern coin showing the nation of issue always is the obverse.

I can defend that the side of the Venezuelan coins with Bolivar's portrait is the obverse. I can also defend that it is the reverse. Maybe I'm just too darned flexible. Anyway, it is a question that is not very important. In the case of Venezuela I just use one side and the other side and people will generally understand.

Peter

[bruce61813]

Comment received from aurelianus in Dutch (my translation) on:

Verdigris   A light to blue green powdery layer on bronze coins, caused by a chemical reaction of copper(I)chloride (CuCl). When left untreated, verdigris will destroy a coin.

Verdigris is the trivial name of copper(II)acetate. This is not the same as copper(I)chloride and it is not an active constituant in bronze rot.

My questions: 1) What is verdigris in English? 2) What is the word for the effect I mention in the description?

Peter

1. Verdigris is the common name for the chemical Cu(CH3COO)2, or copper(II) acetate. It commonly occurs by the action of acetic acid when copper, brass or bronze is weathered and exposed to air or seawater over a period of time.
It can destroy a coin or bronze artifact so that part is correct. An it is the same in English

2.  copper chloride CuCl , is commonly referred to as "Bronze Disease", and will destroy bronze, if not stopped
    A longer explanation is posted at: http://www.gringgottscoins.com/wst_page2.html

Both are blue-green in color and are the result of acids reacting with the bronze, and treatment would be with a sodium carbonate & sodium bi-carbonate solution.

Bruce

[Figleaf]

Thanks, Bruce. Any suggestions on how to incorporate this into the list of numismatic terms?

Peter

[bruce61813]

Peter try this: I would change your definitions:

Verdigris -  the common name for the chemical Cu(CH3COO)2, or copper(II) acetate. It commonly occurs by the action of acetic acid when copper, brass or bronze is weathered and exposed to air or seawater over a period of time. It can destroy a coin or bronze artifact so that part is correct. An it is the same in English

Copper chloride (CuCl)  -  is commonly referred to as "Bronze Disease". A pale blue-green powdery coating on bronze . It is an acid attack, NaCl + water = NaOH + HCl, the Hcl will attack the bronze matrix forming the CuCl + CuO. It  will destroy bronze, if not stopped
   
Tin Pest - At 13.2 degrees Celsius (about 56 degrees Fahrenheit) and below, pure tin transforms from the (silvery, ductile) allotrope of β-modification white tin to brittle, α-modification grey tin. Eventually it decomposes into powder, hence the name tin pest. The decomposition will catalyze itself, which is why the reaction seems to speed up once it starts; the mere presence of tin pest leads to more tin pest. Tin objects at low temperatures will simply disintegrate.

Zinc Pest - http://en.wikipedia.org/wiki/Zinc_pest


Bruce


Bruce





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[Figleaf]

Thanks, Bruce. Done.

Peter

[bruce61813]

Great Peter, and a Happy New Year to you and every one here on world of Coins!

Bruce

[Bimat]

Comment received from aurelianus in Dutch (my translation) on:

 2) What is the word for the effect I mention in the description?

Peter

Aah..Here comes my subject of interest
The reason for writing Copper as Copper (I) is to show its oxidation state i.e.+1.As copper is a transition element,it can show 3 different oxidation states-+1,+2 and +3.Hence,compound CuCl₂ also exists.To avoid the confusion between the two compounds,most of the transition metal compounds are denoted by the oxidation state of the transition metal.This notation can become critical-for example,The Osmium metal shows 5 different oxidation states-+2,+3,+4,+6,+8.
I hope that helps you

Aditya

[Figleaf]

I appreciate your excellent intentions, Adita, but I am not sure how to fit this into the list of numismatic terms. I also fear that coin collectors are too stubborn to follow that notation ...

Peter

[Bimat]

Ooops..Sorry..I didn't read the very first post completely!! But as Chemistry is my most favorite subject,I thought it is the right place for me Sorry again!!