Featured Rainbow tarnish

Scroll down to Interference Colors here:
https://www.canada.ca/en/conservati...onservation/understanding-silver-tarnish.html

 

I’m just assuming there is a different reflective effect, because silverplate has a base metal underneath.

 

In the coin world tarnish is called toning.

In the US silver coins with rainbow toning fetch a premium.

US 90% silver coins like the 19th century Morgan Dollar used to naturally tone because of their copper alloy and the fact that they were wrapped in sulfur / sulphur infused brown paper rolls.

The premium on rainbow toning has resulted in many US sellers/ dealers, faking the toning by using eggs, banana skin inside brown paper bags, placing coins inside potato's and baking them.
Placing coins in sealed containers along with matches.
This is called AT (Artificial Toning)

Some US sellers get carried away and advertise them as "Monster Toned"
Its all baloney in my eyes.

In the UK, Victorian 92.5% (Sterling ) silver coins did not achieve the same amount of natural toning because of the conditions they were stored in and some variations in alloys.

Hardly anyone if anyone at all fakes tarnish / toning on coins in the UK because collectors over here and probably the rest of the world don't give a rats ass about it.

I know of two other ways of tarnishing silver coins and any other silver for that matter.

#1 is burying the item in yellow sulphur powder, an hour will turn the coin, the longer it is left the darker it goes.

#2 Is paint the item with "Gun Blue" and rinse off after a few hours.

 

In my opinion it depends in what conditions the item is kept in, dampness, pollution etc.

I once bought a picture frame containing several British silver Crowns, Victoria, George III, William IV, George V.
They were rainbow toned on the exposed side and shiny silver on inside.
The frame had hung in a pub for about 40 years and was exposed to daily tobacco smoke.

 

Silverplate is only millimeters of coating. It also have a different chemical make up. Over time as some gets worn away from polishing, I think the interference colors present differently, if I’m understanding it correctly.

 

Here is one of the said tobacco rainbow toned Crowns.
This one is 50% silver



Here is a much younger Canadian 80% silver coin, found in a rusty tin.