Hello all,i found those pieces in the shore of a river, it turned out that they have big amount of silver in them.I made even analysis.... does someone have found anythnig simmilar?
Aluminum is light, so does the slag have any weight to it or does it feel light? It sure looks like melted Aluminum slag but if your testing method is sound and states otherwise, maybe something else.
Did you find this in a state where precious metals have been found?
Maybe get a precious metals acid testing kit to confirm. If its silver, it will give a reaction. I think it's turns blue but can't remember exactly. I don't have a acid testing kit but thought about getting one as I sometimes pick up junk silver here and there at flea markets, etc.
There are solders with high silver content - used in brazing. I use silver solder to add "keepers" to fish-hooks for soft baits (it doesn't corrode). Sorry for blurry image.
Silver solder uses - Silver (Au), copper (Cu) and tin (Sn).
I would agree with Charlie P. It looks like it could be a brazing alloy, with the main ingredients being mostly silver and copper. I see on McMaster-Carr that they have one with 72% silver and 28% copper. I didn't do an exhaustive look.