I'm curious how do you authenticate the bars you are buying?
As few months ago I bought 7 silver 1oz 999 bars from different locations. And i ended with 5 nickel! All of the nickel bars were perfectly coated with 1mm 999 silver and tests originally reacted to silver. Then just when i start having some suspicions due to bar's size, re-applied test at the same spot few times shown that the bars are not silver.
There are a few things you can do to test, and I use multiple methods. It can often be simple to fool one test, but if you use multiple tests it gets much harder. BTW where did you buy them from? eBay I assume? Some pictures would be appreciated if it is not too much trouble. I like to know what the recently circulating fakes look like.
1. Try to buy from known trusted vendors.
2. Know what legitimate bars/rounds look like
3. Know what the genuine coloration/finish looks like
4. Check weight, anything significantly higher or lower than the stated weight is a bad sign
5. With acid tests it is best to sand down an area to make sure you are not just testing a silver plate. Many acid test kits include a block with which to do this. You can test what you scratched off directly on the block.
6. A simple test you can do is place an ice cube on your silver and see how long it takes to melt. Since silver is highly conductive it should melt very fast. You can compare with a bar you know is silver to know how long it should take
7. Check the tone of the sound it makes when it is tapped with a hard object. Real silver has a very distinctive ringing tone
8. Silver is diamagnetic, this means it will create an electrical field around it when it comes into contact with a strong magnetic field. If you run a strong neodymium magnet over your silver you will feel resistance as you pass over it. Be aware other metals are diamagnetic as well, so this test alone is not proof.
There are more, some are simple, some are expensive. Do a little research and you will find there are plenty of ways you can simply test your bars and rounds to be sure they are real.
Sorry about the delayed answer but it's summer time
Yes, I bought them from eBay but I don't the list of sellers now. However I can tell you how I catch that there are fake bars - by volume! As all ordered bars was 1oz, they all should have the same volume (W x H x Z). But then some came with a higher or smaller volume from previous and this raised my suspicion.
Than you and for the advises how to test it.
