How to test for genuine silver coins?

Hi all,

I have a few old Chinese silver coins from the Empire and Republic era that I found in my house. As there is a chronic counterfeit market in China, is there any quick and easy way to test them?

Also, there is a coin that turned brown-ish. I don't think silver can tarnish like this?

thanks
fliegendeholländer

https://en.numista.com/numisdoc/measure-a-coin-s-density-27.html

 Perhaps that might help ?

Cool thanks. Silver doesn't rust does it?

Yes silver does oxidise and the natural products of siler are silver nitrate AgNO3, silver(II) fluoride AgF2, potassium tetrafluoroargentate K[AgF4] and valence state of +1 meaning it has a single electron in the outer orbit. Hydrogen sulfide reacks giving silver sulfide and that is why the coin turns black.

Silver can only oxidize to black as I remember it. I have one that is the colour of.... light brown. This probably means it's not silver?

You can always try a magnet.  Silver shouldn't stick, as long as it's a high purity.  

The only elements that are least able to react are the noble gases, silver does react with other elements and it is worth while you learning about silver so you can deal with any problems you may encounter.

From my little experience, fake Chinese coins are same weight and diameter as real one. As silver is  denser than cheaper metals, fakes are thicker. So, once you figured out reference data, possibly using density measurement, it might be easier to check weight, diameter and thickness than measuring density of every single coin.
Notice that fakes use copper which doesn't react to magnets.
Other posts on this forum also mention that some fakes use designs or obverse/reverse combinations that don't exist.