Not likely solid silver. Silver plating does the same thing as solid silver in terms of tarnish blackening a cleaning cloth. Magnetic is a sure sign of not silver, but in most cases the base metals used in silver plated things are non-magnetic so that does not help in terms of saying it is silver. Hallmarks are helpful in saying which, but you mention there are no markings so that does not help other than to point to not silver and rather silver plated. No one has mentioned acid testing - they make acids that can tell if something is silver, but the huge problem with those is they only tell you what is on the surface and so silver plate will test the same as solid silver. You can gouge down deep into the metal and acid test down deep in the metal, but that is so destructive that it is only worth doing on metal that you intend to melt down for its bullion value and not on something that you want to keep.
The best clue is the part of the metal that looks coppery colored. That is base metal with the silver plating worn off. Without having it in my hand to examine this is only "very likely" rather than absolute, but from the photos it looks very likely that it is not silver.