Is it Silver??

I know this subject has been discussed a thousand times, so sorry if this is boring.

Besides metal detecting, I also enjoy auctions, and there is usually a few items that are supposed to be silver, or could be silver. The problem is that there is no way I can determine if the object is silver or something else. The auctions that I go to, are not letting you scratch or use any chemicals to do any test. The closest I get to testing, is using a magnet. Weighing doesent help, since I have no way of knowing what the object would weigh if it were silver. I have run into lots of fake Chinese silver dollars, but the magnet works well on those. Some items are marked sterling, but others are just stamped with unknown marks. Most items are Asian or British, and could be anything from coins, jewelry to religious items.   

So, is there any non-destructive  way to determine if the object is silver, and also in a short amount of time.